As experts in Cisco Professional Services, the 4CornerNetworks blog covers a wide range of Cisco Network related topics. Our blog features topics from Cisco Support Services, Cisco Engineers and our specialist blogs based on Cisco Security.
Head of Security Deyan Panchev writes about Cisco Security providing advice, tips and insights into topics such as Cisco Firepower services, Cisco ASA Firewall Support, Installations and Deployments. Topical issues about network security are also discussed on our blog ranging from the NGFW (Next Generation Firewalls) to the recent Wannacry outbreak.
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New extremely large Botnet is being built – Nicknamed IoTroop or IoT Reaper
Remember Mira? The worm that prayed on unsecure IoT devices. It managed to spread and gain control using quite a simple method to gain entry – reusing the hard-coded or default password for IoT devices which were well-known by then, and the spreading was done via the EthernalBlue SMB exploit.
Now security researchers at CheckPoint and NetLab360 claim there is a new botnet being formed (called IoTroop or Reaper). This time the methods used to gain unauthorized entry are more sophisticated – no more trying to exploit traditional hardcoded and default password or to brute-force easy passwords, the Reaper malware tries to exploit different known vulnerabilities that IoT and home network devices have (more than 12 different popular vendors including Linksys, Netgear, D-Link, AVTECH and GoAhead have numerous vulnerabilities already discovered, list and links in the related articles below). The Reaper code constantly evolves, the guys behind it seems to add new exploits into the code based on new vulnerabilities being published openly on the Internet.
Another key difference between Mirai and Reaper is that as Mirai was extremely aggressive in scanning and trying to hop between network and infect other systems (which makes it easily detectable by security controls), the Reaper is stealthier in its way of spreading and tries to stay under the radar for as long as possible.
The likelihood of a successful exploit is quite high due to the fact that traditional home users do not tend to pay much attention to security and are very likely not to have patched their devices.
All sources claim this new botnet will be much bigger and stronger than Mirai – The NetLab360 researchers are claiming the C2 communication they see confirms more than 20k bots per control server and they have estimated more than 2 million vulnerable devices out there that are ripe for the infection. There is a great possibility the total number of bots can swell quite heavily in the coming weeks.
What is at stake here? How will this botnet be used?
At this stage, it is still very early to predict how this botnet will be used but most likely DDoS attacks are on the roadmap – the previous smaller Mirai successfully managed to do a DDoS with more than 1Tbps of traffic (both to Dyn internet infrastructure giant which brought down many popular web services down and French hosting company OVH).
IoT general security problems
The problems with IoT is the inherited lack of security (saying inherited because manufactures do not take security into account when building the devices) and the ever-growing number of IoT devices being deployed by users who are not savvy in networking or security best-practices (changing of default passwords, patching, lowering the attack surface). These two large issues combined with the large number of devices out there (the trend is more and more IoT devices to be manufactured and connected online) really poses quite a large security threat to the Internet community.
Some good news:
Different efforts to secure IoT devices are on the roadmap, US lawmakers are trying to pass a legislative action into forcing hardware IoT manufactures to start taking security into account and not spill out junky unsecure devices.
Also, some of the creators and botnet administrators of the Mirai, have now been arrested and expecting trial and effective sentences. This clearly shows there will be consequence for all actions related to running a botnet and malicious cyber behavior, this must be a deterrent for any future black-hats out there.
New ransomware on the loose
Remember WannaCry and Nyatya, aka NotPetya (a variant of Petya) ransomwares. There is a new one around the corner (initial spotting is on the 24th Oct), again spread predominately in the East Europe (Ukraine, Poland, Bulgaria) and Russia but also in Japan, Germany, South Korea and the USA. It is a changed version of NotPetya. It uses usually a drive-by download on hacked sites to trick the user to run a fake Flash Player installer. The horizontal spread within the compromised network this time is NOT based on the EthernalBlue SMB exploit, but Bad Rabbit uses an open tool MimiKatz to try to extract any login credentials on the infected machine and reuse them to spread itself via legit Windows management protocols such as WMI and SMB to other devices. It also uses a hard-coded list with most commonly used passwords to try to brute-force credentials access.
Most current antivirus and endpoint protection software will detect Bad Rabbit and there is a known Windows Registry based vaccination that can prevent a machine from getting infected, but Bad Rabbit shows the ransomware trend is still strong and not likely to quiet down anytime soon.
We live in interesting times
There is a Chinese proverb/curse saying: May you live in interesting times?
Why is this intended as a curse? Maybe living in interesting times means living in challenging times.
The security environment is so dynamic these days, it is certainly interesting to see how things change all the time, vulnerabilities are found almost every day, exploits are being developed at a whopping pace and even for professionals, just keeping up with it all is very challenging.
In the last two weeks there have been quite a few major security events/discoveries
Starting with KRACK ATTACK (announced 18th of Oct), which our blog already covered https://4cornernetworks.com/krackattack-kraken-wi-fi-wpa2/ but there are new things around the corner.
New VPN/crypto attack – DUNK (Don’t Use Hard-coded Keys) attack
With KRACK attack still going on strong there is a new one that involves breaking cryptography. This one however does not take advantage of the control messages in WPA-2 to allow sniffing of user data but exploits weak software implementation for the ANSI X9.31 RNG. Until quite recently the ANSI X9.31 RNG was used to generate cryptographic keys that secure VPN connections and web browsing sessions.
A team of security researchers from the University of Pennsylvania and John Hopkins University found a vulnerability that affects devices using the ANSI X9.31 Random Number Generator (RNG) in conjunction with a hard-coded seed key. The DUHK attack allows “attackers to recover secret encryption keys from vulnerable implementations to decrypt and read communications passing over VPN connections or encrypted web sessions”.
The attack has been confirmed to work on Fortinet devices running FortiOS 4.3.0 to FortiOS 4.3.18. The necessary requirement (all of them need to be met) for a device to be vulnerable to the DUHK are:
- It uses the X9.31 random number generator
- The seed key used by the generator is hard-coded into the implementation
- The output from the random number generator is directly used to generate cryptographic key
- At least some of the random numbers before or after those used to make the keys are transmitted unencrypted. This is typically the case for SSL/TLS and IPsec.
Also, the attacker needs to be able to observe passively the encrypted handshake traffic.
The X9.31 was widely deployed in the past and was even part of the FIPS approved random number generation algorithms set until January 2016. There is a big chance a lot of VPN implementations are still using it.
There is a CVE for this vulnerability: CVE-2016-8492:
Here are the general recommendations:
- If you are a Fortinet client, please make sure your FortiOS is not running versions 4.3.0 to 4.3.18, or else upgrade asap.
- If you are running any cryptographic software still using the X9.31 generator, reconfigure it to use other random number generator or replace/upgrade software.
- Always stick to the latest security approved cryptographic algorithms when creating VPNs. Legacy VPN should be reconfigured to follow the latest practices
Wi-Fi is everywhere, everything is on Wi-Fi now, phones, tablets, laptops, even home PCs, game consoles, smart devices (IoT), sensors etc. The security of WiFI is imperative, and has been entrusted to the WPA2 protocol. For that protocol, thus far all exploits have been connected to guessing the security key (hence reliant on customers having a weak key) or surrounding technologies (WPS for example) or older implementation such as the TKIP.
None of them were successful against a strong security-minded implementation.
The attack – high-level breakdown of how the attack works and which devices are affected
An extremely interesting paper was released (16th October 2017) by its author, Mathy Vanhoef, this paper would rock the world of Wi-Fi as shines light on how to exploit the WPA2 protocol in such a way as to be able to decrypt the user data.
How does the attack work?
The attack does not allow the attacker to join the protected WiFi, nor does it break the encryption key. The attack is focused on the management plane in the WPA2, more precisely on 4-way handshake exchange during the client join. It is achieved by manipulating and replaying handshake messages. By replaying message 3 of the handshake the attacker has the ability reinstall an already used nonce instead of a fresh key (a replay is allowed by the protocol because messages can be lost due to low signal etc). To guarantee security, an encryption key combination (key+nonce) should be used only once, then different versions of it (different nonce) should be used. Reusing the same key and nonce allows the attacker to derive the keystream, which combined with knowing a portion of the data that is encrypted and the already encrypted data, is enough to decrypt the rest of the data.
The attacker is positioning himself/herself in the middle of the handshake between the AP and the client by using a spoofed WiFI SSID with same name and making the client join his SSID by advising him to switch channels (hence the attack works best if the client has stronger signal to the attacker than to the legit AP). Only when this man-in-the-middle is completed can the attacker manipulate this handshake (as described above) and starting decrypting what the user sends.
Who is affected? – Practically every Wi-Fi enabled client, as again this is an attack towards the WPA2 protocol itself which all vendors needed to follow in their implementations, so this is not a scenario when the exploit is possible due to bugs in the code.
Android and Linux are the ones that are easier to compromise to the fact they mostly (41% of the devices out there) use wpa supplicant version 2.4. With them the code developers have followed a WPA2 standard advice to delete the nonce after its use so when the replay of message 3 happens the nonce that is used is comprised only from zeros making it trivial to decrypt. Further finding from the same author describe the possibility for that attack to work (with few changes) also towards wpa_supplicant 2.6 and iOS and freeBSD clients. This latest update brings the percentage of vulnerable supplicant to a very high number (as the author states, if you have a phone it is most likely vulnerable).
We are sending out massive amount of sensitive data using Wi-Fi these days. Username and passwords are just the start, but credit card information, personal IDs, emails, private pictures etc. I guess nobody wants that data to be shared and read by others. Furthermore, the top choice device for many of these, is your smart phone, which in fact is the most vulnerable type of client device (see Conclusions chapter below).
So, what is next?
Do we go back to WPA or WEP or wait for WPA3?
Answer is no, WPA is also vulnerable and WEP is even less secure, WPA2 can be amended (both as a protocol and as implementation in software) and will continue to be used. It is recommended that WPA2 with CCMP is used, as TKIP and GCMP are even easier to break and attackers can not only listen to data but also manipulate data so malware can be injected into the traffic.
How to protect ourselves
Only the software update can mitigate this attack. Keep a close eye to the vendor announcement and patch as soon as they release the security patch for this exploit. Some of the patches may be silently releases and installed on your devices but please make sure you have them.
Actions like changing your PSK password and such do not make any difference (remember, the attack does not reveal this password nor lets the attacker join your network).
Deploy additional levels of encryption that is independent of the WPA2, such as SSL/TLS or IPSec. In the example on the krackattack page, they were only able to read the data from the web site after striping the SSL from it which in fact is a misconfiguration on the website itself.
The current threat is obviously for the end devices, not the infrastructure devices (APs etc). I expect that Microsoft, Apple and other commercial major OS vendors will react very fast and will silently patch (if they have not done so already). That would be sufficient for laptops and PCs with enabled Wi-Fi. A bigger problem will be for smart phone users, every Android vendor (Samsung, HTC etc) dictates its patching schedules, so I am not expecting a fast reaction from them. Apple runs its own devices so I expect faster reaction.
Having put the spotlight on client devices and not infrastructure, it is mandatory to mention that this new type of attack and the sure-to-come spin-offs from it will lead to new attacks towards infrastructure devices.
Cisco has numerous products that are found vulnerable and still investigating many more for that possibility.
As you probably know the Equifax (one of the three big credit bureaus in North America and UK) announced it was breached (discovered unauthorized access) on the 29th of July. So far, the predictions are that this leak of sensitive personal data impacts over 143 Million American, Canadian and British citizens.
What is a credit bureau? – an organization that makes money by gathering and compiling huge amount of data (personal and financial) about customers and selling it to 3rd party marketers with the purpose of being able to provide a credit score for a certain individual to prove that customers’ financial capability when obtaining credit.
Obviously, these incredibly detailed dossiers contain tons of sensitive information that could be used to impersonate a person for either financial gain or to cause harm.
Historically speaking, all credit bureaus have encountered problems keeping their sensitive information secure, Experian for example had a breach in 2015 which exposed data for over 15 Million people.
Analysis of the breach:
As investigation is on the way (after the detection of the breach in July, Equifax has hired a security company to investigate all details of the breach and the depth of the data leakage and to do proper forensics), there are few released details on what really happened. But what is known so far is very troubling and does not look good for Equifax cyber-security posture. The official statement from Equifax is that the attackers broke into the company’s systems by exploiting an application vulnerability and then gained access to certain files. No mention of the exact vulnerability used which facilitated the breach. The fact that there is no mention of zero-day vulnerability (unknown flow), which could in fact make Equifax less culpable and makes sense for them to highlight, means that the vulnerability was known, meaning that Equifax were not patching on time their internet accessible public services nor had properly configured advanced IPS or security control in place, both are a must when you operate with such highly sensitive data. Other security best practices were obviously not followed by allowing the attackers to get real data after breaching an internet edge service.
- A long delay in announcing the breach. This could be explained with the ongoing internal investigation but still the delay could have been used by hackers to their advantage to harm Equifax customers.
- Equifax reaction after the announcement
Equifax came up with a plan to offer some kind of post factum sense of security to its customers and announced a new portal (www.equifaxsecurity2017.com) where its customers might be able to check if their personal and financial information was amongst the ones that were stolen. However, this portal did not give any such information but usually it was either not working (gave System Unavailable message probably due to high load) or was experiencing certificate issues and hence has been blocked by many web security solutions (such as Cisco OpenDNS) or when they finally got it to work – was giving unclear information, a possible scheduled date for enrolling to another service (credit protection) called TrustedID. On top of that some security researchers have noticed that this output is being presented whether the customer presents real data (the portal asks for Last name and last 6 digits of social security number) or fake made up one. Seems this portal is nothing but an attention diversion from the real problem.
- Equifax had problems with the company security vision/leadership
Equifax until recently was looking to hire a vice president of security (they see that position to fulfil the role of a CISO). This position is vital for a company which possess such sensitive information and should not be left vacant. Cyber-security is a mindset and it takes time and persistence to be built. It should always come from the top positions in a large company and have the backing of top managers.
Lessons to learn:
Some simple cyber-security lessons to learn
- Know your assets and their value, this will give you an idea on how much you need to invest in protecting these assets
- Know the risks to your assets and what impact would a damage or leakage have on your company
- Have a strategy/vision that is supported and driven by top management
- Take action to put that strategy in place
- Have a plan in case of a breach, that would help you react and restore your positions, gain back trust from your customers and do proper analysis/forensics of the breach
A new malware Nyetya (combination of words from Nye Petya, meaning NOT Petya), also known as Petrwrap and GoldenEye has been spreading globally over the last 24 hours.
This virus is distinct from WannaCry and other initially suspected variants, it has some unique new features which makes it harder to detect and defend against, clearly showing that today’s malware landscape is an evolving space. This rapidly changing threat landscape has a number of factors including; leaked tools from government agencies, more advanced security controls that require advanced malware (the cat and mouse game) or just because attackers are more determined and more capable.
Other popular researchers (links below) say Nyetya is more of a nation (state) attack towards a specific country (Ukraine) that is disguised as ransomware so its true nature would remain hidden in the shadow of recent WannaCry ransomware.
Some Characteristics of Nyetya and why it is different
- There is recent research that showed Nyetya, despite having major resemblance to Petya ransomware, in fact does not keep a copy of the encrypted MTL (Master File Table) and MBR (Master Boot Record) that it replaces with the random note. That means that even in the case that the user gets its decryption keys there is nothing to decrypt. This behavior resembles specific type of malware called Wiper Malware. All machines that are infected cannot be recovered. Also, the email for contract with the attackers is now disabled so there is no possibility for getting the decryption keys. Obviously, the attackers have not intended to milk the ransom and get rich for their efforts.
- It encrypts the master boot record, which makes the whole system unusable and causes more damage. Previous crypto viruses (ransomware) were encrypting specific file extensions
- It does not use a common attack vector from the Internet
It does not infect by scanning ports for vulnerable services, nor uses phishing (mails with crafted content with specific covert malware links), nor file attachments or web sites that host malicious content. Instead the initial way in was via an update in a polular accounting software in Ukraine (called MeDoc). The software was tricked into auto-updating with a malicious file (Perfc.dat). Once it is inside it uses the Eternal Blue (SMBv1) exploit to spread (same as WannaCry) but also two other administrative tools (PSexec and WMI) which in general are valid and legitimate tools used inside a network. The use of these tools would not raise any alarms on network security controls. The malware is capable of stealing the current user’s token and use it to distribute itself to other devices via PSexec (still unclear how it is able to steal the token) or again to steal the current user credentials and use them via WMI.
- No external Internet scans
There is no evidence of external scans (from the internet) in order to locate unpatched SMB services. The only scans that the virus conducts are horizontal, once it is inside the protected network. That makes the virus very hard to detect as most organisations do not have visibility within their network for such activity
- No Command and Control functionality
The virus does not use C&C so any reputation based security controls cannot detect it. IP addresses/domains reputation is widely used to detect zero-day attacks and to monitor the spread of the virus. That does not seem feasible protection from Nyetya
- Special attention has been paid to cleaning up any remaining data and logs
All of these unique characteristics point to the fact that cyber criminals have changed their tactics (after the failure of WannaCry due to the incidental but timely discovery of the killswitch) and want the malware spread to be as stealthy as possible.
Protecting yourself from the attack
A short summary of techniques necessary to protect against the attacks are listed below. These cannot be undertaken in isolation and it is assumed that good security practices are already in place such as disaster recovery strategy as well security control such anti-malware controls.
- Patch your systems (MS17-010 should be applied), close off any SMBv1 services (disable)
- Do not use admin/elevated privileged accounts for normal users
- Monitor your network and endpoints for PSexec and WMI communication and try to establish if that is valid communication (could be based on which one the administrators use and also the time of the day)
- Monitor your internal network segments using an IDS/IPS
Which type of network security controls are best suited to discover and prevent malware spread?
While other forms of malware attack may have been stopped by reputation based or email and web security controls, neither would have been effective in this instance. An essential tool in the armoury of security controls is endpoint security such as Cisco AMP for Endpoints, which actively analyse the behaviour of executable files on the system and perform sandboxing.
IDS/IPS network controls are able to catch lateral scans and spread via SMBv1 exploit only if they can see the traffic (actively monitoring traffic on the same logical domain). The most common IDS/IPS deployment model is on the Internet edge, as this malware does not use external scans or gets distributed via normal Internet related channels (mail and web) these controls are not effective.
Following general security best practises is also beneficial – having backup of important systems/files, having proper application visible monitoring on the network and trying to detect unusual behavior, that of course requires both the tools and the people (analyst).
Cisco currently has multiple endpoint security solutions in place – CWS (Cloud Web Security / Scansafe), Umbrella (OpenDNS) and AMP for endpoints are prime examples. AMP is a different breed of endpoint protection, it relies heavily on detection based on heuristics and cloud sandboxing, where as CWS and OpenDNS both concentrate very strongly on making sure your Internet browsing is secure and save.
A bit of history behind the story: when Cisco acquired Scansafe and then sometime later OpenDNS, a lot of people were wondering why Cisco needs two products that have such a large overlap in functionality. At first CWS looked like it was going to last, it had a large customer base, was heavily pushed by Cisco Sales and managed to get a big boost from existing Cisco customers that needed protections for this security gap which was opened by remote/roaming employees.
OpenDNS with most of its customers using the free version seemed like an outsider. It could only detect things based on DNS and was not tunneling any traffic back to the cloud, so it seems like it is not going to be a valid corporate level endpoint protections tool. People underestimated the power of DNS. OpenDNS has something very valuable, via its free version, it had the ability to see a large percentage of worldwide DNS request and using its strong security team it provided a more universal and complete protections that focuses on more than just web browsing. Almost all internet communication is based on DNS, the use of static IPs has been greatly reduced for couple of reasons – for non-malicious users the DNS provides first ease of use and flexibility that static IPs could not, for malicious users – the use of static IPs proved to be unwise as IPs were very quickly blocked (blacklisted) by ISPs and security tools. The result of massive DNS use was that your DNS provider could actively see where your traffic is going and block it (monitoring and enforcement) for all applications (not only Web based).
It was clear Cisco would have to make a choice and I believe they have made the correct one – Cisco is moving forward with the Umbrella and retiring the CWS.
What is Umbrella?
In short, the paid version of OpenDNS, which can support and integrate with other Cisco Products.
How does it work?
It works by forwarding DNS request to OpenDNS servers, either by registering your public IP with Umbrella and forwarding your internal DNS to OpenDNS servers, or by setting your network equipment (DHCP) to directly give out OpenDNS servers for DNS usage, in case the company does not have own internal DNS servers. That secures devices within the offices of the company. For Roaming devices, Umbrella has a Roaming Client (a small agent installed on endpoints, supports Windows and MACs, with vision to support Linux in the future) that makes sure all DNS requests are forwarded to the OpenDNS cloud.
It is very important to note that Umbrella does not work like a traditional Web Proxy, it does not send the all user traffic to the cloud for inspection, it only works and makes decisions based on the information from the DNS requests from the client. User traffic is send for inspection to the cloud only for gray/risky domains (traffic to malicious ones is blocked straight away). Furthermore, this redirection of traffic works for both Agent and Agentless deployments by using the DNS reply to forward the traffic to the Umbrella Cloud proxy service called Umbrella Intelligent Proxy.
The result is a better user experience (instantaneous decision to allow and block traffic to majority of traffic based on good and bad domains), lower deployment complexity and lower operational costs.
How is it configured?
Umbrella is one of the easiest deployments we have seen. It has excellent documentation and simple steps to help you redirect your office traffic to the cloud and deploy Roaming clients to your endpoints. All the management is done via portal in the web (https://dashboard.umbrella.com/). It has a very simple and effective portal layout with intuitive access to both management entities (managed identities and policies) but also monitoring and reporting. A typical simple implementation of Umbrella can be done in a matter of hours, without the need of any on-premise hardware installations (except when AD integration is needed, a lightweight virtual server needs to be installed)
Does it support AD integration for enhanced user visibility?
Yes, it does, it needs a VA (Virtual Appliance, a lightweight virtual server running on either ESX or Hyper-V). The VA servers allows Umbrella to see internal information such as private IP addresses of users and further performs an AD integration with MS AD (servers as a connector) so Umbrella Dashboard can see AD names and be able to define policies based on groups and create reports that include clients AD username (very handy if you want to know who exactly is making all of these malicious outbound requests (such as Command and Control traffic et).
Can it block based on connections that do not use DNS?
Yes, it can, there is a functionality called IP Layer Enforcement that builds IPSEC tunnels to the Umbrella cloud and forward requests to it in case the connection has a suspicious (flagged as malicious) IP address. This is possible only if the client is using Roaming Agent (either the Umbrella one or Anyconnect one).
Does it have integration with other Cisco products?
Umbrella has a module for Anyconnect (Cisco Umbrella Roaming Security module is available for Anyconnect version 4.3 MR1 and newer), which means if the customer has Anyconnect already deployed, there is no need to install Umbrella Roaming Agent. Also, OpenDNS security team is now part of Cisco Talos so OpenDNS both feeds Talos with DNS information but also benefits from Talos to device either certain domain or IP address are deemed risky.
Does it support SSL decryption?
Yes, Umbrella supports SSL decryption so it can do deep inspection for traffic destined for risky/suspicious domains. The configuration of the SSL decryption is very straight-forward, administrators are prompted to download Umbrella (OpenDNS) certificated from the Dashboard and then these certificates need to be installed as trusted on endpoint machines. Next step is just to enable the SSL decryption.
Umbrella provides enterprise level endpoint security with lower latency than traditional proxies, low capex and deployment costs.
As you might be aware this Friday (12th of May 2017) there was a massive outbreak of a new type of crypto virus dubbed WannaCrypto aka WannaCry. The UK was hit the hardest, especially in the Health Sector, with Spanish Telecom – Telefonica, along with Portuguese & Argentinian telecoms and Russia.
How does that affect the UK? – The NHS is badly crippled (more than 30 hospitals reported malware spread), patients are being turned away, important data such as scans and personal test results are lost and planned surgeries are cancelled. We could easily say that lives are at stake as sometimes more critical operations had to be postponed or done without important tests/scan results.
About the attack:
The WannaCry outbreak is the quickest spread of malware ever (over 100 countries with many affected endpoints in a matter of hours).
This link shows the spread over time. The animation was made possible because the authors of MalwareTech, could hack into one of the Command and Control domains and gain control over it so they can trace the incoming call home requests from the hacked machines (keep in mind that this does not depict the whole spread of the virus as MalwareTech operated in EST time and the spread in Europe and Asia was already going for some hours).
Another unique thing – the virus exploited a vulnerability in Windows OS systems that was used for years by the NSA and GCHQ government agencies but only revealed for the public a couple of months ago (by the ShadowBroker dump on the 14th of April)
Here the Security Industry in the world are divided in their opinions.
One opinion is that the vulnerability should have never been leaked so bad guys would not be aware of it and hence would not be able to exploit it. This is usually the opinion of non-hardened security guys since it loudly shouts – Security through Obscurity or the ostrich effect.
The second opinion is that not a single discovered vulnerability should remain hidden, the more people are aware of the threat, the more people can react to it. General security admins had more than two months to patch their systems as official patch from Microsoft was released quickly after the leak (official patch was released on the March 14th). One important note was that many government, slow and big organization (due their sheer size and bureaucracy) are still running Windows XP and since XP is out of life and support, there was no patch for it – An example for such organization was the NHS.
The virus had a kill switch designed by its creators, a hidden nonsense long domain that if alive will make the virus stop spreading. A researcher found it by looking at the malware (reverse engineering it) and he was not sure why is was there, so he registered the domain and luckily helped in stopping the spread (the malware checks if that domain is alive before attempting worm like spread in the same L2 network)
The Onion Router
Botnet Command and Control centres are located in TOR (the onion router)
OK, that has been done before so not quite unique but very hard to implement as the malware needs to download a whole lot of files to the end user device to make this work. The technique is adding anonymity to the guys running the botnet (hence the creators of the malware). CC is very important for Crypto Viruses as these are usually created not to destroy but to extort money out of people who want their files recovered and recovery is done via this backchannel by supplying the key. If people pay and their files do not get recovered the rumour spreads and people accept their losses and do not pay anything. The current estimation for infected systems with encrypted files is more than $55 000 and attackers want an average of £300 for endpoint recovery, that amounts to a hefty ransom sum (if 20 000 users pay, that is over 6 million dollars).
Heavily customised and detailed interaction user/victim – The information displayed to the user explains in detail what has happened and what needs to be done (how to pay) to recover your files and it is translated and shown in 28 languages. The presentation (ransom note below) is done via an executable file and offers many options.
How does the attack work?
The malware uses a vulnerability in the SMBv2 remote code execution in Microsoft Windows. The exploit (codenamed “EternalBlue”) has been made available on the internet through the Shadowbrokers dump on April 14th, 2017 and patched by Microsoft on March 14. Usually, SMB’s are not directly connected to the outside world, the attack point was via email as well as the spread or a quick vertical scan for port TCP 445. After initial infection, the virus spread like a worm, probing all hosts within the subnet for open SMB ports and trying to infect them. Also, quite unique for this virus is that it uses different services for performing different tasks, aka Modular Service approach – for example, it uses different services for file dumping, for finding files with particularly important extensions and encrypting them, for disabling the shadow copy/system restore, for presenting the screen with the note/demands/payment information – yes that is a separate executable file.
- Patch – regular/automated patching of windows systems would have prevented the malware to do any damage by removing the vulnerability that should be exploited
- Security Training – organisation employees should be aware of the dangers of executing files from emails or clicking on links
- Advanced malware protection on the endpoints – could stop the execution of the malware in the first stage or downloading and installation of the malware in the second stage
- Email security – strong email security would have greatly reduced the spread of the malware or disabled any executable files from being delivered to the users (depends on tuning, but even files with unknown status should be held back and guaranteed before further analysis can be done) or will check URLs in mails and you determine if you able to click on them (more modern Email protection systems have built in Web URL protections)
- Web security controls – would help in cases when the infection point happens by URL link in email
- Advanced IPS with Command and Control botnet detection – would not be effective in the first minutes of the spread but will quickly update itself (depending on vendor) and will detect/drop outgoing CC connections. Traditional firewalls with stateful technology would not help except by blocking SMB traffic based on TCP 139/445 ports (however traditional firewall deployment does not scan east to west traffic and traffic in the same L2 network)
- Backup your important information in a separate secure location – a reactive approach but very effective towards crypto viruses
Mitigation techniques (after the attack)
Unfortunately, after files are encrypted, it is close to impossible to decrypt them without having the proper key. Most endpoint protection companies give you a list of things to do to remove the virus, hinder its spread, and be immune in the future but not to recover files. General recommendation varies between different vendors but most of them follow these steps.
- Make sure your endpoint protection software is running and not disabled by virus.
- Download latest signatures
- Install the PATCH from Microsoft (MS17-010) which fixed the SMBv2 vulnerability
- Scan all systems, the virus is detected (usually by the name MEM: Trojan.Win64.EquationDrug.gen), and reboot the system (before that make sure you have the patch installed).
Indicators of compromise
How to check if your network has the malware. Typical indications are listed in the link below
Basically, you must request certain IPs on the Internet and you have seen a file transfer with the mentioned SHA-256 fingerprint (keep in mind there is small variations of the virus so there is multiple fingerprints)
Virtual Private Networks constitute a hot topic in networking because they provide low cost and secure communications between sites (site-to-site VPNs) whilst improving productivity by extending corporate networks to remote users (remote access VPNs). Naturally the VPN technology is widely deployed on all internet edge devices and most ASAs.
Cisco is very proud of its VPN solutions. It’s one of the few vendors that support such a wide range of VPN technologies with so many features and flexibility. Cisco Routers and Cisco ASA Firewalls are the two types of devices that are used most often to build Cisco Virtual Private Networks. Cisco has been very strict about the way its routers and firewalls should be used and what technologies are available to them – routers will do the full range of Site-To-Site of VPNs: Traditional (Policy-based) IPsec VPNs, but also GRE IPsec VPNs, DMVPNs, GET VPNs, and have limited capabilities for the remote access VPNs: IPsec and SSL based. However, the ASA is very different so far it could do just traditional policy based L2L IPsec VPN but will have the full functionality for remote based VPNs. The message was very clear, for large organization and ISP use Routers for remote access VPN and static traditional Site-to-Site use the ASAs.
Things changed, Cisco very recently introduced a new feature with its 9.7.x code in the VPN module of the ASA – the VTI (Virtual Tunnel Interface). VTI were long available in Cisco Routers but never in Cisco Firewalls but similar technologies (Route-Based VPNs) were available in most competitors and the demand for that features finally took effect on Cisco and they introduced it.
Now before understanding why VTI are so important we will do a quick comparison between the traditional Site-to-Site IPsec VPN (Policy Based VPNs) and the VTI (Route-Based VPNs)
Policy Based VPNs
They rely on static (policy based) configuration of the encryption domain (usually by ACLs) and do not pass multicasts, not great for dynamic routing and voice/video and other multicast applications and requires re-configuration on both sides if the networks that traverse the VPN should change. The configuration is quite complex involving many steps that need to be same or mirrored (encryption domains/ACL config) and that is prone to mistakes.
However, the benefits are that this is a well matured configuration process and the IPsec VPN is a IETF standard which means all vendors must implement it according to the specifications of the standard, hence in theory it should always work between in multivendor scenarios. This is important because the two main uses of L2L (Site-to-Site) VPNs is connecting same company sites over internet thus replacing more expensive intranets or connecting one company to another company/partner/provider of services over Internet in a secure manner. In that second case, there is a big chance that both companies will use different vendors for VPN devices.
A route-based VPN configuration uses Layer3 routed tunnel interfaces (either GRE based or VTI based) as the endpoints of the VPN. Instead of selecting a static subset of traffic to pass through the VPN tunnel using an Access List, all traffic passing through the special Layer3 tunnel interface is placed into the VPN. Therefore, you need to configure routing accordingly. Either a dynamic routing protocol (such as EIGRP or OSPF) or static routing must be configured to divert VPN traffic through the special Layer3 tunnel interface. That makes the selection of interesting traffic dynamic and you have the flexibility to perform changes and introduce new traffic to the VPN without redoing the VPN configuration (only by changing the routing so new traffic gets routed to the interface). Another benefit is that this type of VPN can pass multicast traffic thus allowing dynamic routing protocols and enabling multicast applications to work.
There are some limitation and considerations that need to be taken in mind. First VTI is a proprietary to Cisco technology, despite other vendors having similar route-based VPN technology, there is no guarantee these will work between each other. Also, the tunnel interface itself does not provide inherited security, IPsec protection is an add-on and needs to be configured on top for encryption/security of traffic.
Summary and conclusions:
Introducing VTIs in ASAs is a big step forward in making the firewall an even more versatile network edge device. The VTI capability to provide security and encryption on multicast traffic and its flexibility for tunneling the traffic via dynamic routing with zero reconfiguration on the VPN, means that any small or middle-sized organization with ASA on network edge can now benefit very strongly from that functionality and would not need to purchase additional hardware thus maximizing its return on investment value.
Cisco has finally decided to merge its two major network security products – the ASA and FirePOWER. These two have been living on the same hardware (5500X) model for years now but they required separate management which increased the deployment and operational costs for a Cisco FirePOWER implementation. Now Cisco has decided to merge these two platforms by removing the logical separation in hardware and the full separation in software by creating a merged OS that combines the features of both worlds, hence lowering the time/costs for deployment and running.
A bit of History
Cisco is a major player in the Firewall Market since the PIX. With the introduction of the first gen ASA, the PIX was given a polish, new features (such as dynamic routing, QoS, new RFC based protocol inspections/fixup and a few more), but ASA’s were and still are a traditional stateful packet firewall positioned at the Internet Edge. The demands to introduce firewalls also in the DC drove the change from IP based object to Name based object and totally different way of doing NAT (including the introduction of the Any as interface) in versions 8.3+. Still the ASA was purely a stateful firewall and the IDS/IPS module that Cisco was offering was quite outdated in technology and had a less than excellent catch-rate. Cisco knew that and purchased the best IPS/IDS vendor out there – SourceFire.
Now Cisco had two flagmen in the network security and naturally decided to offer them as one box – hence the NX 5500X Firewalls were created, no modules needed, all you need to run both ASA and FirePOWER was an upgrade to SSD drives. However, the management, logging, operation of the ASA and FirePOWER was still independent – ASA was managed and monitored by either ASDM or CSM, where FirePOWER was using – FireSight (pre-version 6) and now FMC (Firepower Management Center). Most competitors (Palo Alto and Check Point) did not need nor have separate management platforms to configure their advanced Next-Gen capabilities and frankly speaking users/admins were not happy with having to do double amount of work to enable a Cisco Next Gen Firewall – interfaces, licensing, configuration, policies, monitoring etc.
In 2015 Cisco hinted about the concept of having one unified management OS that would combine the features of both FirePOWER and ASA. The FirePOWER was chosen as a base for that new image, so from day one the FTD image had almost a 100% of the FirePOWER functionality but a very small percentage of the ASA functionality. The first release (6.0) for testing and Cisco partners was in 2016 and then the FTP had about 20% of the features of the ASA – basic features of course were migrated first, but shockingly there was lack of some major features such as – HA, VPNs (both site-to-site and Anyconnect), dynamic routing protocols, virtualization/contexts, QoS. A quick introduction of 6.0.1 and 6.1 introduced HA failover so the FTD was now ready to go public.
The Situation today
Latest version release early 2017 is 6.2.0
Cisco continued its work to close the gap between the current ASA and FTD functionality. New major functionality added: Clustering for ASA, Site-To-Site IPSec VPN with certificates (6.1 supported Site-to-Site VPN but only with Pre-Shared-Key), PKI support, SGT without Realm, Migration tool (from traditional ASA to FTD), REST API, Packet Tracer and Capture functionality.
On top of the migrated in 6.1 functionalities such as integrations with Cisco ISE, Threat Grip, on-box management for some model, the 6.2 is looking more and more enterprise ready (not only SOHO as the 6.0 and 6.1). Also, adding the tools for automated migration, the FTD becomes more easily available when doing migration. The user base is also enlarging quite quickly (good for discovering of bugs and security/stability issues). Version 6.2.1 is just around the corner and will close the gap even further introducing the Anyconnect Remote Access functionality and many improvements/new features in NAT, Dynamic Routing, Multicast and QoS, HA, Site-To-Site VPN and interestingly an option for conversion back to ASA image.
This all points that soon there will be a major swift in the Cisco Security community and more and more clients will start using FTD. Naturally after break-point Cisco will start the phase out of the traditional ASA image (functionality gap will be in favor of the FTD) and clients will be forced to switch. Of course, that process will take time but why not be ahead of the curve?