The ISO file has two main components.
The _meta.txt contains a PowerShell script, which is encrypted with a substitution cipher.
The downloader.exe is a .NET assembly.
It has a big dictionary with the substitution alphabet to decrypt the PowerShell script in _meta.txt.
It adds the PowerShell commands as scheduled task named ChromeTask which runs every ten minutes.
Other variants of the same malware use dictionaries to combine words into a task name.
The downloader.exe also shows an error message to the user, claiming that the operating system is incompatible with the program.
The PowerShell script downloads the Chrome extension archive.zip from a malware server and installs it.
Due to the scheduled task this continues to happen every ten minutes.
This explains why some Reddit users complain that Chrome closes itself all the time.
This is a mishap of the malware developer because the annoyance factor will make it more likely that affected users clean their system as soon as possible.
Malicious Chrome extension
The Chrome extension itself has not been analysed yet.
Possibly because of its hefty obfuscation.
While trying to debug the extension within Chrome, it’s already noted that the extension settings chrome://extensions are redirected to the general settings chrome://settings.
This prevents users from uninstalling the extension within Chrome.
The extension consists of four files.
The application icon is called properties.png and shows a gearwheel.
The manifest.json is part of every Chrome extension and has some metadata, e.g., about the icon location, extension name and permissions.
The config.js contains the name of the extension, version number, C2 server and some form of id named _dd which is always sent as parameter to the server.
The main script is the background.js.
It features control flow obfuscation via switch-case statement hopping which cannot be deobfuscated automatically by currently available tools.
After identifying v0MM.T7 and v0MM.o7 as the ancor points for function string decoding, by replacing the calls to these functions with their return value.
The extension’s main functionality is to serve advertisments and hijack search requests to Google, Yahoo and Bing.
Every three hours analytics are sent to the C2.
The extension requests advertisments from the C2 server every 30 minutes.
The following image shows the extension’s request to the C2 server in the first line and the server response in the second. The server provided a direct download link for a legitimate software product.
Sign Up For Threat Alerts
Dec 01, 2022
UNC4191 Threat Group Targets Entities In The...
The UNC4191 threat group was discovered targeting entities in the Philippines with custom malware and...
Nov 30, 2022
Emotet Leads To Quantum Ransomware Infection
Threat actors were observed using Emotet to gain access to the victim's network and deploy...
Nov 29, 2022
RansomExx Upgrades to Rust
IBM Security X-Force Threat Researchers have discovered a new variant of the RansomExx ransomware that...
Nov 29, 2022
Ransomware Roundup: Cryptonite Ransomware
FortiGuard Labs has reported on Cryptonite ransomware, which was found to target Microsoft Windows machines...
Nov 28, 2022
Operation Typhoon: The Cyber Sea Lotus Coveting...
Cyber espionage actors, now designated by FireEye as APT32 (OceanLotus Group), are carrying out intrusions...
Nov 27, 2022
IL-Cert Alert – Active phishing campaign in...
There is a new phishing campaign in Israel. The malware relies upon user execution. The...
Nov 27, 2022
Emotets Vacation Is Over: No Rest For...
Emotet started as a banking Trojan in spreading via spam campaigns by imitating financial statements,...
Nov 24, 2022
Aurora: A Rising Stealer Flying Under The...
Aurora is a multipurpose botnet with data collection, information stealer, downloading, and remote access Trojan...
Nov 23, 2022
Analysis Of The ViperSoftX And VenomSoftX Information...
Torrents and software-sharing sites are being used to target victims across the globe with variants...
Nov 22, 2022
Wipers have existed for years, and while they haven't been utilized as much as ransomware,...
Nov 21, 2022
LockBit 3.0 Ransomware Unlocked
Also known as LockBit Black, this ransomware family announced itself stating that it would now...
Nov 21, 2022
Control Panel Executable Abused For QakBot Infection
QakBot campaign modifies deployment tactics and aims to exploit a DLL hijacking technique that abuses...
Nov 20, 2022
Earth Preta Spear-Phishing Governments Worldwide
Trend Micro teams have been monitoring a wave of spear-phishing attacks targeting the government, academic,...
Nov 20, 2022
CISA Alert (AA22-321A) – Hive Ransomware Analysis
Threat actors are using Hive ransomware variants to target the government, communication, critical manufacturing, information...
Nov 16, 2022
DTrack activity targeting Europe and Latin America
DTrack is a backdoor used by the Lazarus group. It is used by the Lazarus...