Cybersecurity researchers have uncovered a novel malware marketing campaign that leverages Google Sheets as a command-and-control (C2) mechanism.
The exercise, detected by Proofpoint beginning August 5, 2024, impersonates tax authorities from governments in Europe, Asia, and the U.S., with the purpose of focusing on over 70 organizations worldwide by way of a bespoke device referred to as Voldemort that is geared up to assemble data and ship extra payloads.
Focused sectors embody insurance coverage, aerospace, transportation, academia, finance, know-how, industrial, healthcare, automotive, hospitality, vitality, authorities, media, manufacturing, telecom, and social profit organizations.
The suspected cyber espionage marketing campaign has not been attributed to a selected named risk actor. As many as 20,000 e-mail messages have been despatched as a part of the assaults.
These emails declare to be from tax authorities within the U.S., the U.Okay., France, Germany, Italy, India, and Japan, alerting recipients about modifications to their tax filings and urging them to click on on Google AMP Cache URLs that redirect customers to an intermediate touchdown web page.
What the web page does is examine the Person-Agent string to find out if the working system is Home windows, and in that case, leverage the search-ms: URI protocol handler to show a Home windows shortcut (LNK) file that makes use of an Adobe Acrobat Reader to masquerade as a PDF file in an try and trick the sufferer into launching it.
“If the LNK is executed, it’s going to invoke PowerShell to run Python.exe from a 3rd WebDAV share on the identical tunnel (library), passing a Python script on a fourth share (useful resource) on the identical host as an argument,” Proofpoint researchers Tommy Madjar, Pim Trouerbach, and Selena Larson mentioned.
“This causes Python to run the script with out downloading any information to the pc, with dependencies being loaded instantly from the WebDAV share.”
The Python script is designed to assemble system data and ship the info within the type of a Base64-encoded string to an actor-controlled area, after which it reveals a decoy PDF to the person and downloads a password-protected ZIP file from OpenDrive.
The ZIP archive, for its half, accommodates two information, a reliable executable “CiscoCollabHost.exe” that is prone to DLL side-loading and a malicious DLL “CiscoSparkLauncher.dll” (i.e., Voldemort) file that is sideloaded.
Voldemort is a customized backdoor written in C that comes with capabilities for data gathering and loading next-stage payloads, with the malware using Google Sheets for C2, information exfiltration, and executing instructions from the operators.
Proofpoint described the exercise as aligned to superior persistent threats (APT) however carrying “cybercrime vibes” owing to the usage of methods widespread within the e-crime panorama.
“Menace actors abuse file schema URIs to entry exterior file sharing assets for malware staging, particularly WebDAV and Server Message Block (SMB). That is achieved through the use of the schema ‘file://’ and pointing to a distant server internet hosting the malicious content material,” the researchers mentioned.
This method has been more and more prevalent amongst malware households that act as preliminary entry brokers (IABs), reminiscent of Latrodectus, DarkGate, and XWorm.
Moreover, Proofpoint mentioned it was capable of learn the contents of the Google Sheet, figuring out a complete of six victims, together with one which’s believed to be both a sandbox or a “identified researcher.”
The marketing campaign has been branded uncommon, elevating the chance that the risk actors forged a large web earlier than zeroing in on a small pool of targets. It is also potential that the attackers, possible with various ranges of technical experience, deliberate to contaminate a number of organizations.
“Whereas most of the marketing campaign traits align with cybercriminal risk exercise, we assess that is possible espionage exercise performed to help as but unknown last aims,” the researchers mentioned.
“The Frankensteinian amalgamation of intelligent and complicated capabilities, paired with very primary methods and performance, makes it tough to evaluate the extent of the risk actor’s functionality and decide with excessive confidence the final word objectives of the marketing campaign.”
The event comes as Netskope Menace Labs uncovered an up to date model of the Latrodectus (model 1.4) that comes with a brand new C2 endpoint and provides two new backdoor instructions that permit it to obtain shellcode from a specified server and retrieve arbitrary information from a distant location.
“Latrodectus has been evolving fairly quick, including new options to its payload,” safety researcher Leandro Fróes mentioned. “The understanding of the updates utilized to its payload permits defenders to maintain automated pipelines correctly set in addition to use the data for additional trying to find new variants.”