New Variant of Notorious Svpeng Currently for Sale on the Russian Underground

In recent days, there have been numerous reports about the new Svpeng variant, with extended capabilities. These capabilities include keystroke logging and taking control of many device functions, using the accessibility services feature. Continue reading “New Variant of Notorious Svpeng Currently for Sale on the Russian Underground”

Shadow Brokers’ Massive Leak Spreads Quickly Across the Dark Web

Since April 14th, when the Shadow Brokers leaked a new batch of files allegedly affiliated with Equation Group – an APT threat actor suspected of being tied to the NSA – Darknet forum members have been sharing the leaked attack tools and zero-day exploits among themselves. Continue reading “Shadow Brokers’ Massive Leak Spreads Quickly Across the Dark Web”

The IoT Threat – Infographic

2016 made IoT one of the hottest topics across the cyber security industry as Internet-connected devices became a major tool for DDoS attacks. Researchers expect that the role of IoT will only grow in the coming years. Although very recent, the first signs for this new threat vector were visible over the past two years, with malicious actors engaging in IoT exploitability and attacks utilizing these devices. In fact, IoT botnets are not new. In 2015, Continue reading “The IoT Threat – Infographic”

SenseCy’s Predictions for the Cyber Global Arena in 2017 – Infographic

2016 witnessed an unprecedented volume of cyber events of varying impact and future significance. Following a detailed analysis of those events deemed to have the most strategic future ramifications, we have identified a number of major trends and concerning developments expected to gain momentum in 2017. Check out our new Continue reading “SenseCy’s Predictions for the Cyber Global Arena in 2017 – Infographic”

Exploit Kits Out, Loaders and Macros Back in

During 2016, we witnessed the collapse of three major exploit kits that were previously used for massive malware delivery: Nuclear (first), Angler and then Neutrino (later). Along with other more private EKs (such as Magnitude), they caused major damage in previous years and served as infection vectors for many malicious malware-distributing campaigns. Continue reading “Exploit Kits Out, Loaders and Macros Back in”

The Shade (Troldesh) Ransomware: One More Soldier in the Army of Encryption Miscreants

Written by Mickael S. and Tanya K.

Last week, SenseCy analysts happened upon a new sample of Shade ransomware, also known as Troldesh, which uses a no_more_ransom extension for encrypted files. This ransomware is far from famous, lacking the glorious Continue reading “The Shade (Troldesh) Ransomware: One More Soldier in the Army of Encryption Miscreants”

Jihadi Cybercrime (Increasing Interest in Spam and Phishing Methods on Closed Islamic State Platforms)

While monitoring closed platforms that propagate an Islamic State agenda, we detected an initial interest in hacking lessons, focusing on spam and phishing methods. Many discussions in the technical sections of closed platforms affiliated with the Islamic State deal with the implementation of Continue reading “Jihadi Cybercrime (Increasing Interest in Spam and Phishing Methods on Closed Islamic State Platforms)”

Anna-senpai – Analysis of the Threat Actor behind the Leak of Mirai

The Mirai IoT Botnet has made a lot of headlines in recent weeks. While the botnet itself was analyzed and discussed by a number of security researchers and companies, none addressed the threat actor behind the recent attacks and the leak of Mirai source code. Such an analysis can provide useful insights into Continue reading “Anna-senpai – Analysis of the Threat Actor behind the Leak of Mirai”

Cerber Ransomware JavaScript Loader Goes Undetected

We have been closely monitoring Cerber ransomware since it first emerged on a Russian password-protected forum, offered as-a-service for members only.

At present, Cerber ransomware constitutes a sophisticated malware threat to organizations. (it was responsible for more than 25% of the total number of ransomware infections recorded worldwide in June 2016, according to Microsoft). Files encrypted by Cerber are currently non-decryptable.

On August 23, 2016, a member of the same closed forum where Cerber ransomware is traded posted a detailed analysis of the loader that the malware uses to install itself. According to his post, he did this after hearing that the loader is very useful and capable of installing any malware without detection. His conclusion was that the loader does not employ any extraordinary methods to install the ransomware, but its tremendous advantage of being fully undetectable by AV programs is due to the usage of several rare code functions that are difficult to emulate.

First, he posted the full obfuscated code of the loader, explaining parts of it:

  • Replacement of the Eval function, i.e. it receives a parameter that contains JavaScript code and executes it. Usually, AV programs emulate this function. Replacing the Eval function blocks this emulation.
  • Another part of the code creates a Desktop shortcut, probably also as an anti-emulator measure (the post writer comments that in his opinion AV would quickly detect it).
  • The next part of the code is obfuscated – a HEX code which is divided and deobfuscated using XOR.After deobfuscation, we can see that the code contains anti-emulation.
  • Then a random string is created and a path from %TEMP% environment obtained for it.
  • The next stage involves downloading the malicious file from an URL address and saving it in the system.
  • A parameter is added to the header to block AV bots and researchers: setRequestHeader(‘cerber’,’true’)
  • If the malicious payload was downloaded properly, it is executed.
  • Finally, the Eval alternative is launched.

Summarizing the analysis, the post author concludes that the advantages of the loader are a good implementation of the payload download and execution and errors control. The disadvantages he mentions are weak implementation of obfuscation and anti-emulation, and low level of usability functionality. He also attached an AV scanner report from August 23, showing a detection rate of 15/40.

Several days later, on August 27, 2016, the same forum member posted that he had analyzed the latest version of the loader and was surprised by the fact it is totally undetectable by AV programs. Moreover, this version is capable of installing payloads from several alternative URL addresses and it uses improved debugging. This version does not use anti-emulation at all, but employs a unique method that totally blocks the AV syntax emulation. 

Below is a description of the main techniques used by the loader to remain undetected:

  • Replacement of the Eval function (even though it is a simple technique, it is used extensively by JS packers and therefore cannot be detected by AV as malicious).
  • The part of the code that avoids emulation is an array that contains random data, with the first element being the important one. The functions Math.floor and Math.random always output only the first element in the array and AV cannot properly emulate them. Full undetectability is achieved by using these two functions.

The emulator will always output one single value and will never reach the part of the array when the right value is located. As a result, the emulator cannot perform the calculations, a critical error occurs and the AV programs are unable to identify the loader as a malicious file.

1
The message that analyzes what code feature allows the malware to avoid AV detection

The post author attached an AV scanner report showing a 0/35 detection rate (as of August 27, 2016).

2
The scan showing that the loader is not detected by AV engines