Pierluigi Paganini November 19, 2022

Cisco Talos spotted multiple updated versions of LodaRAT that were deployed alongside other malware families, including RedLine and Neshta.

Researchers from Cisco Talos have monitored the LodaRAT malware over the course of 2022 and recently discovered multiple updated versions that have been deployed alongside other malware families, including RedLine and Neshta.

The versions include new functionality to spread to attached removable storage, a new string encoding algorithm and the removal of “dead” functions

LodaRAT is written in AutoIt, the researchers pointed out that it is easy to obtain its original source code from the compiled binaries by using an AutoIt decompiler.

Samples of the LodaRAT discovered in the wild use function obfuscation and string encoding to prevent being analyzed. However, experts reported that there are many examples of malware that are not obfuscated, their analysis can allow threat actors to access to the original code and create their own variants of LodaRAT. Another weakness in the malware is the lack of encryption for C2 communications which makes it trivial to implement a custom C2 infrastructure.

“This ease of source code retrieval and customization has likely contributed to the proliferation of numerous variants and customized versions of LodaRAT.” reads the report published by Talos. “It is quite common to find altered versions of LodaRAT, and it should be expected that most samples will likely have some sort of alteration to the source code.”

One of the heavily altered versions of LodaRAT analyzed by Talos used a totally rewritten function that detects anti-malware processes. The new function searches for thirty different process names, but this new implementation is far less effective than the previous one because it will not detect a product that is not included in the list of processes to search for.

The list of processes also includes discontinued security software such as ByteHero, and Norman Virus Control.

Many new malware versions also removed some functionalities to avoid detection.

“Many of the LodaRAT samples we analyzed have removed functionality in some way, which may be the author’s attempt to reduce detection rates. The most common removal appears to be the PowerShell keylogger typically found in earlier versions.” continues the report.

During their research, Talos experts observed the LodaRAT being delivered through a previously unknown variant of the commodity trojan Venom RAT.

The bundling of LodaRAT alongside Neshta and RedLine Stealer has also been something of a puzzle, although it’s being suspected that “LodaRAT is preferred by the attacker for performing a particular function.”

“Over the course of LodaRAT’s lifetime, the implant has gone through numerous changes and continues to evolve. While some of these changes appear to be purely for an increase in speed and efficiency, or reduction in file size, some changes make Loda a more capable malware. As it grows in popularity, it is reasonable to expect additional alterations in future.” concludes the report. “The ease of access to its source code makes LodaRAT an attractive tool for any threat actor who is interested in its capabilities.”

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Pierluigi Paganini

(SecurityAffairs – hacking, LodaRAT)

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