The Latrodectus malware, initially identified by Walmart in late 2023, has recently undergone significant upgrades with the release of version 1.4. This iteration, which bears notable similarities to the infamous IcedID malware, showcases advanced capabilities and enhanced evasion techniques. The malware’s evolution highlights its increasing sophistication, posing a growing threat to cybersecurity.
Latrodectus version 1.4 introduces several critical updates designed to improve its effectiveness and concealment. Key among these is a new string deobfuscation approach that employs AES256 encryption in CTR mode, replacing the previous XOR method. This sophisticated encryption uses hardcoded AES keys and variable initialization vectors (IVs) for each string, complicating the decryption process and making the malware more challenging to analyze.
The malware’s delivery mechanisms have also evolved. Initially spread through email spam campaigns orchestrated by threat actors TA577 and TA578, Latrodectus has recently been delivered via a BRC4 badger. The infection process begins with a heavily obfuscated JavaScript file, which executes embedded code to download and install a malicious MSI file. This MSI file then uses the Windows tool rundll32.exe to load a DLL named “nvidia.dll,” which is obfuscated with a crypto tool previously used by other malware.
New features in version 1.4 include two additional commands that enhance its operational flexibility. Command 0x16 allows the malware to download and execute shellcode from a remote server, while Command 0x19 enables it to download files to the %AppData% directory, facilitating the deployment of further payloads. Detection of Latrodectus has been identified by threat protection solutions such as Netskope Threat Protection, which uses signatures like Gen
.Ulise.493872 and Trojan.Generic.36724146. The ongoing development and sophisticated nature of Latrodectus underscore the necessity for continuous vigilance and adaptation in cybersecurity strategies.
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