Streams of malicious emails Talos inspects every day usually consist of active spamming campaigns for various ransomware families, phishing campaigns and the common malware family suspects such as banking Trojans and bots..
It is however often more interesting to analyze campaigns smaller in volume as they might contain more interesting malware. A few weeks ago I became interested in just such a campaign with a smaller number of circulating email messages. The email, first of them submitted from Middle East, purports to be coming from a Turkish trading company, which might further indicate the geographic area where the attacks were active.
Analyzing malware is often like solving a puzzle, you have to do it piece by piece to reach the final image. In this case I spent more time analyzing the campaign than I initially planned. The campaign has many stages of the infection chain and all needed to be unraveled before the final payload level was reached. Furthermore, each of the stages used different development platform and was obfuscated in a different way. But let us start from the beginning.
When the WannaCry attack was launched a little over a week ago, it was one of the first large scale attacks leveraging the data that was leaked by the Shadow Brokers. At the time the real concern was how quickly we would begin to see other threats leverage the same vulnerabilities. Over the past couple of weeks, Talos has observed other malware variants that are using the ETERNALBLUE and DOUBLEPULSAR exploits from the Shadow Brokers release as part of their campaigns. Among them were Adylkuzz, Uiwix, and EternalRocks.
Adylkuzz is a piece of malware that uses ETERNALBLUE and DOUBLEPULSAR to install cryptocurrency mining software on the infected system. This attack actually pre-dates the WannaCry attack and has continued to deliver the cryptocurrency miner.
Uiwix uses a similar technique to install ransomware on the infected system. When the files are encrypted, the file names include “UIWIX” as part of the file extension. The key difference with this malware is that, unlike WannaCry, the Ransomware doesn’t “worm itself.” It only installs itself on the system.
Talos is monitoring the major Exploit Kits(EK) on an ongoing basis. While investigating the changes we recently observed in the RIG EK campaigns, we identified another well known candidate: Terror Exploit Kit.
Terror EK is one of the new players who showed up after the big Exploit Kit market consolidation last year. When Angler and friends disappeared new EKs started to try their luck. Many of them were far from Angler’s quality. One of these was Terror EK which appeared end of last year. It started with a very simple version,carpet bombing the victims with many exploits at the same time, no matter if the exploit matched the victim’s browser environment or not. Unfortunately, they improved the kit step by step and we saw a fast evolution up to the latest version analysed in this report.
We identified a potentially compromised legitimate web site acting as a malware gate, redirecting visitors initially to a RIG exploit kit landing page, then switching to Terror exploit kit one day later.
This may indicate how these campaigns collaborate and share resources, or possibly one campaign pirating another. Terror seems to constantly evolving. In this campaign it has added further exploits and no longer carpet bombs the victim. Instead it evaluates data regarding the victim’s environment and then picks potentially successful exploits depending on the victim’s operating system, patch level, browser version and installed plugins. This makes it harder for an investigator to fully uncover which exploits they have.
It is interesting to note that the adversaries are using an URL parameter in cleartext for the vulnerability they are going to exploit, e.g. cve2013-2551 = cve20132551 in the URL.
When Talos decided to make a threat intelligence podcast, we wanted to make it different than your typical buttoned down, subdued security podcast. The BWT crew: Craig, Joel, Nigel, and Mitch, decided to do that by making a podcast that is a lot like the discussions that you would have after work with colleagues – if your colleagues were both ridiculously opinionated and hyper-focused on security research. Occasionally we’ll even have some special guests join us.
Talos is disclosing the presence of two vulnerabilities in the Artifex MuPDF renderer. MuPDF is a lightweight PDF parsing and rendering library featuring high fidelity graphics, high speed, and compact code size which makes it a fairly popular PDF library for embedding in different projects, especially mobile and web applications. Both of these vulnerabilities, if exploited, could lead to arbitrary code execution of an attacker’s choice on the target device. Both of these vulnerabilities have been responsibly disclosed and Artifex has released software updates to address these vulnerabilities.
Two memory corruption vulnerabilities exist within Artifex MuPDF render that could result in arbitrary code execution if exploited. These two vulnerabilities manifest as a result of improperly parsing and handling parts of a PDF file.
A major ransomware attack has affected many organizations across across the world reportedly including Telefonica in Spain, the National Health Service in the UK, and FedEx in the US. The malware responsible for this attack is a ransomware variant known as ‘WannaCry’.
The malware then has the capability to scan heavily over TCP port 445 (Server Message Block/SMB), spreading similar to a worm, compromising hosts, encrypting files stored on them then demanding a ransom payment in the form of Bitcoin.
Organizations should ensure that devices running Windows are fully patched and deployed in accordance with best practices. Additionally, organizations should have SMB ports (139, 445) blocked from all externally accessible hosts.
Please note this threat is still under active investigation, the situation may change as we learn more or as our adversary responds to our actions. Talos will continue to actively monitor and analyze this situation for new developments and respond accordingly. As a result, new coverage may be developed or existing coverage adapted and/or modified at a later date. For comments and questions, please follow the link below to the Talos Intelligence blog, comments here have been closed to keep conversation in one forum. For current information, please refer to your Firepower Management Center or Snort.org.