Security Experts:

Coding Errors in Shamoon Malware Suggest It May Be Work of Amateurs

The Disttrack/Shamoon malware, while destructive, appears to be the work of amateurs and not elite and sophisticated developers, according to the latest analysis.

Kaspersky Lab released additional details of its research into the Disttrack/Shamoon malware that is capable of erasing all the information on the computer and then destroying its Master Boot Record so that it can't boot up again. The malware proved that it was possible for developers to subvert legitimate kernel-mode applications for malicious purposes, Dmitry Tarakanov, a researcher at Kaspersky Lab, wrote on the Securelist blog Wednesday. However, it appears that the malware could have been even more destructive and dangerous, if it had not been for a series of programming mistakes in the code, according to Tarakanov's analysis.

Earlier analysis revealed that the malware was using legitimate signed drivers of RawDisk, a disk management tool from Eldos, in order to rewrite the MBR. However, it turned out Windows 7 gives that ability to applications running with administrator privileges, so it's not clear why the authors even bothered with the driver. There are parameters set at the beginning that is not used when calling the RawDisk function, Tarakanov said.

There were "clues that people behind creating the Shamoon malware are not high-profile programmers," Tarakanov wrote.

The communication module is another example. The command-and-control server is hard-coded as two addresses, which limits the tool since if the address ever changes, the infected machine can no longer receive instructions. The module is also designed to execute an arbitrary program that it downloads from the C&C server, but a "silly error" prevents it from working, Tarakanov said. The error happens to be the use of an uppercase letter instead of a lowercase one in a command string, causing the function to fail.

Burning American Flag Used in Shamoon Malware"The Shamoon malware does not have a functionality to execute other programs," Tarakanov said.

Legitimate and signed drivers that can be used for malicious purposes are "like gold dust" to malware developers, Tarakanov said. Software developers need to develop methods to "efficiently prevent" untrusted applications to get access to drivers as attackers search for covert ways to access a system’s resources.

"The nature of their mistakes suggest that they are amateurs, albeit skillful amateurs as they did create a quite practiceable piece of self-replicating destructive malware," Tarakanov concluded.

Researchers from AlienVault Threat Center released a technical analysis of the malware on Tuesday, focusing on how administrators can detect the infection and remove it before any damage can be done. The report contains IDS rules that can be loaded on to the sensors to detect traffic from the malware's reporter module, which transmits the list of files on the system to the C&C server. The report also included a signature that would detect if the machine was compromise that administrators could use in their monitoring efforts.

AlienVault had specific recommendations for administrators, such as configuring network shares to prevent write access and to remove open shares, updating the antivirus, and isolating critical networks. Administrators should be monitoring the network to detect the "indicators of compromise" detailed in the report, as well as activating logging on domain controllers to audit how domain credentials are being used, AlienVault said.

The developers behind the malware were most likely motivated by political reasons, Taraknov said, noting that the malware overwrote existing files with a fragment of an image of a burning American flag. "They wished that their protest which was embedded into the malware would not go unnoticed," Tarakanov said. He also said there was still no definitive way to tell whether this was the malware that destroyed oil company Saudi Aramco's computers last month.

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Fahmida Y. Rashid is a Senior Contributing Writer for SecurityWeek. She has experience writing and reviewing security, core Internet infrastructure, open source, networking, and storage. Before setting out her journalism shingle, she spent nine years as a help-desk technician, software and Web application developer, network administrator, and technology consultant.