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New Agent Tesla Malware Variant Boosts Evasion Capabilities
KnowBe4 documented an Agent Tesla v4 campaign using emoji-based code obfuscation to evade detection.
KnowBe4 researchers reported a campaign distributing Agent Tesla v4, a long-running Windows keylogger and infostealer. The new variant uses emoji-based code obfuscation, a novel technique, to hinder static analysis and evade security tooling. Defenders should watch for behavioral indicators such as credential theft and unusual process activity.
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Upatre Continued to Evolve with new Anti
Unit 42 analyzes an undocumented Upatre downloader variant with VM detection via process hashing, packed code, disabled Windows defenses and Namecoin .bit C2 domains.
Unit 42 analyzed an Upatre downloader variant compiled in December 2016 that went largely undetected by automated systems, featuring heavy code flow obscuration, on-demand decryption of network communications, and novel virtual machine detection. The sample enumerates running processes, computes CRC32 hashes XORed with a hard-coded key, and sleeps if analysis-related processes such as vmtoolsd.exe or python.exe are found. It masquerades with Google Chrome icons, disables Windows Defender, Firewall and other security services, injects code into msiexec.exe, and resolves .bit Namecoin domains like bookreader[.]bit via hardcoded OpenNIC DNS servers over TCP.
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