ESET researchers have spotted a new strain of malware tracked as Exaramel that links the dreaded not Petya wiper to the Industroyer ICS malware.

A few months ago, researchers from ESET discovered a new piece of malware that further demonstrates the existence of a link between Industroyer and the NotPetya wiper.

In June 2017, researchers at antivirus firm ESET discovered a new strain of malware, dubbed Industroyer, that was designed to target power grids.

Industroyer was involved in the December 2016 attack aimed at an electrical substation in Ukraine that caused significant power outages.

Industroyer is the fourth malware specifically designed to target ICS systems, threats previously discovered by security experts are Stuxnet, BlackEnergy, and Havex.

Now experts found a link between the 2016 Industroyer attack and Russia-linked APT groups tracked as BlackEnergy, TeleBots, Sandworm, and Electrum.

“That said, we have observed and documented ties between the BlackEnergy attacks – not only those against the Ukrainian power grid but against various sectors and high-value targets – and a series of campaigns (mostly) against the Ukrainian financial sector by the TeleBots group.” reads the analysis published by ESET.

“In June 2017, when many large corporations worldwide were hit by the Diskcoder.C ransomware (aka Petya and NotPetya) – most probably as unintended collateral damage – we discovered that the outbreak started spreading from companies afflicted with a TeleBots backdoor, resulting from the compromise of the popular financial software M.E.Doc.”

The NotPetya Wiper was linked by experts to BlackEnergy and the KillDisk malware that was used the 2015 attack in Ukraine.

In April 2018, ESET discovered a new backdoor tracked as Exaramel that definitively links Industroyer to TeleBots.

Researchers noticed that the configuration data in XML format written by the dropper of Exaramel in the Windows registry includes the security solution used on the compromised system, something similar with Industroyer.

“the attackers are grouping their targets based on the security solutions in use. Similar behavior can be found in the Industroyer toolset – specifically some of the Industroyer backdoors were also disguised as an AV-related service (deployed under the name avtask.exe) and used the same grouping.” continues the analysis.

Experts also found many similarities in the code used for the implementation of the commands in the Exaramel malware and a backdoor from the Industroyer toolset.

Both malware relies on a report file for storing the result output of executed shell commands and launched processes.

The main difference between the backdoor from the Industroyer toolset and the Exaramel backdoor is that the latter uses XML format for communication and configuration instead of a custom binary format.

“Along with the Exaramel backdoor, Telebots group uses some of their old tools, including a password stealer (internally referred as CredRaptor or PAI by the attackers) and a slightly-modified Mimikatz.” continues the analysis.

“The CredRaptor custom password-stealer tool, exclusively used by this group since 2016, has been slightly improved. Unlike previous versions, it collects saved passwords not only from browsers, but also from Outlook and many FTP clients.”

ESET observed only one attack based on the Exaramel that targeted an organization in Ukraine, experts also discovered a Linux backdoor, racked as Linux/Exaramel.A.

“The discovery of Exaramel shows that the TeleBots group is still active in 2018 and the attackers keep improving their tools and tactics.” concludes ESET.

“The strong code similarity between the Win32/Exaramel backdoor and the Industroyer main backdoor is the first publicly presented evidence linking Industroyer to TeleBots, and hence to NotPetya and BlackEnergy. While the possibility of false flags – or a coincidental code sharing by another threat actor – should always be kept in mind when attempting attribution, in this case we consider it unlikely.”

Pierluigi Paganini

( Security Affairs – instant messaging, hacking)

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