Adversaries may encrypt or encode files to obfuscate strings, bytes, and other specific patterns to impede detection. Encrypting and/or encoding file content aims to conceal malicious artifacts within a file used in an intrusion. Many other techniques, such as Software Packing, Steganography, and Embedded Payloads, share this same broad objective. Encrypting and/or encoding files could lead to a lapse in detection of static signatures, only for this malicious content to be revealed (i.e., Deobfuscate/Decode Files or Information) at the time of execution/use.
This type of file obfuscation can be applied to many file artifacts present on victim hosts, such as malware log/configuration and payload files.(Citation: File obfuscation) Files can be encrypted with a hardcoded or user-supplied key, as well as otherwise obfuscated using standard encoding/compression schemes such as Base64.
The entire content of a file may be obfuscated, or just specific functions or values (such as C2 addresses). Encryption and encoding may also be applied in redundant layers for additional protection.
For example, adversaries may abuse password-protected Word documents or self-extracting (SFX) archives as a method of encrypting/encoding a file such as a Phishing payload. These files typically function by attaching the intended archived content to a decompressor stub that is executed when the file is invoked (e.g., User Execution).(Citation: SFX - Encrypted/Encoded File)
Adversaries may also abuse file-specific as well as custom encoding schemes. For example, Byte Order Mark (BOM) headers in text files may be abused to manipulate and obfuscate file content until Command and Scripting Interpreter execution.
View in MITRE ATT&CK®| Capability ID | Capability Description | Mapping Type | ATT&CK ID | ATT&CK Name | Notes |
|---|---|---|---|---|---|
| intel-tdt | Intel Threat Detection Technology | Microsoft Defender | T1027.013 | Encrypted/Encoded File |
Comments
Intel Threat Detection Technology's (Intel TDT) Accelerated Memory Scanning (AMS) enables efficient memory scanning by offloading these operations to the integrated Graphics Processor Unit (integrated GPU) on Intel client SoCs.
Microsoft Defender Antivirus leverages AMS to optimize the detection of polymorphic and fileless attacks, improving resource efficiency and reducing the performance impact on the Central Processing Unit (CPU).
References
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| intel-tdt | Intel Threat Detection Technology | Microsoft Defender | T1027.013 | Encrypted/Encoded File |
Comments
Intel Threat Detection Technology's (Intel TDT) Accelerated Memory Scanning (AMS) enables efficient memory scanning by offloading these operations to the integrated Graphics Processor Unit (integrated GPU) on Intel client SoCs.
Microsoft Defender Antivirus leverages AMS to optimize the detection of polymorphic and fileless attacks, improving resource efficiency and reducing the performance impact on the Central Processing Unit (CPU).
References
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