ĪPT3 obfuscates files or information to help evade defensive measures. ĪPT29 has used encoded PowerShell commands. APT28 has also obfuscated payloads with base64, XOR, and RC4. dll payload using RTL and a custom encryption algorithm. ĪPT19 used Base64 to obfuscate commands and the payload. ĪPT-C-36 has used ConfuserEx to obfuscate its variant of Imminent Monitor, compressed payload and RAT packages, and password protected encrypted email attachments to avoid detection. ĪppleSeed has the ability to Base64 encode its payload and custom encrypt API calls. AppleJeus has also used the open source ADVObfuscation library for its components. ĪppleJeus has XOR-encrypted collected system information prior to sending to a C2. Īnchor has obfuscated code with stack strings and string encryption. Īmadey has obfuscated strings such as antivirus vendor names, domains, files, and others. Agent Tesla has used the Rijndael symmetric encryption algorithm to encrypt strings. Īgent Tesla has had its code obfuscated in an apparent attempt to make analysis difficult. API function names are also reversed, presumably to avoid detection in memory. Most of the strings in ADVSTORESHELL are encrypted with an XOR-based algorithm some strings are also encrypted with 3DES and reversed. Īction RAT's commands, strings, and domains can be Base64 encoded within the payload. Environment variables, aliases, characters, and other platform/language specific semantics can be used to evade signature based detections and application control mechanisms. Īdversaries may also obfuscate commands executed from payloads or directly via a Command and Scripting Interpreter. Payloads may also be split into separate, seemingly benign files that only reveal malicious functionality when reassembled. Portions of files can also be encoded to hide the plain-text strings that would otherwise help defenders with discovery. Adversaries may also use compressed or archived scripts, such as JavaScript. The user may also be required to input a password to open a password protected compressed/encrypted file that was provided by the adversary. Sometimes a user's action may be required to open and Deobfuscate/Decode Files or Information for User Execution. These payloads may be used during Initial Access or later to mitigate detection. Payloads may be compressed, archived, or encrypted in order to avoid detection. This is common behavior that can be used across different platforms and the network to evade defenses. Adversaries may attempt to make an executable or file difficult to discover or analyze by encrypting, encoding, or otherwise obfuscating its contents on the system or in transit.
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