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T1027 Obfuscated Files or Information

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. This is common behavior that can be used across different platforms and the network to evade defenses.

Payloads may be compressed, archived, or encrypted in order to avoid detection. These payloads may be used during Initial Access or later to mitigate detection. Sometimes a user's action may be required to open and Deobfuscate/Decode Files or Information for User Execution. The user may also be required to input a password to open a password protected compressed/encrypted file that was provided by the adversary. (Citation: Volexity PowerDuke November 2016) Adversaries may also use compressed or archived scripts, such as JavaScript.

Portions of files can also be encoded to hide the plain-text strings that would otherwise help defenders with discovery. (Citation: Linux/Cdorked.A We Live Security Analysis) Payloads may also be split into separate, seemingly benign files that only reveal malicious functionality when reassembled. (Citation: Carbon Black Obfuscation Sept 2016)

Adversaries may also abuse Command Obfuscation to obscure commands executed from payloads or directly via Command and Scripting Interpreter. Environment variables, aliases, characters, and other platform/language specific semantics can be used to evade signature based detections and application control mechanisms. (Citation: FireEye Obfuscation June 2017) (Citation: FireEye Revoke-Obfuscation July 2017)(Citation: PaloAlto EncodedCommand March 2017)

View in MITRE ATT&CK®

NIST 800-53 Mappings

Capability ID Capability Description Mapping Type ATT&CK ID ATT&CK Name Notes
CM-06 Configuration Settings mitigates T1027 Obfuscated Files or Information
SI-02 Flaw Remediation mitigates T1027 Obfuscated Files or Information
SI-03 Malicious Code Protection mitigates T1027 Obfuscated Files or Information
SI-07 Software, Firmware, and Information Integrity mitigates T1027 Obfuscated Files or Information
CM-02 Baseline Configuration mitigates T1027 Obfuscated Files or Information
CM-07 Least Functionality mitigates T1027 Obfuscated Files or Information
SI-04 System Monitoring mitigates T1027 Obfuscated Files or Information
AC-03 Access Enforcement mitigates T1027 Obfuscated Files or Information

VERIS Mappings

Capability ID Capability Description Mapping Type ATT&CK ID ATT&CK Name Notes
action.hacking.variety.Evade Defenses Modification of the action (rather than the system, as in 'Disable controls') to avoid detection. related-to T1027 Obfuscated Files or Information
action.hacking.variety.Null byte injection Null byte injection. Child of 'Exploit vuln'. related-to T1027 Obfuscated Files or Information
action.malware.variety.Disable controls Disable or interfere with security controls related-to T1027 Obfuscated Files or Information

Azure Mappings

Capability ID Capability Description Mapping Type ATT&CK ID ATT&CK Name Notes
alerts_for_linux_machines Alerts for Linux Machines technique_scores T1027 Obfuscated Files or Information
Comments
This control only provides detection coverage for the Compile After Delivery sub-technique while not providing detection for all other sub-techniques relevant to the Linux platform or most of its procedure examples. As a result of this minimal coverage, the overall score is assessed as Minimal.
References
  1. https://learn.microsoft.com/en-us/azure/defender-for-cloud/alerts-reference#alerts-linux
alerts_for_windows_machines Alerts for Windows Machines technique_scores T1027 Obfuscated Files or Information
Comments
This control may detect usage of VBScript.Encode and base-64 encoding to obfuscate malicious commands and scripts. The following alerts may be generated: "Detected suspicious execution of VBScript.Encode command", "Detected encoded executable in command line data".
References
  1. https://learn.microsoft.com/en-us/azure/defender-for-cloud/plan-defender-for-servers
  2. https://learn.microsoft.com/en-us/azure/defender-for-cloud/alerts-windows-machines
defender_for_app_service Microsoft Defender for Cloud: Defender for App Service technique_scores T1027 Obfuscated Files or Information
Comments
This control only covers one platform and procedure for one of this technique's sub-techniques, resulting in a Minimal score.
References
  1. https://learn.microsoft.com/en-us/azure/defender-for-cloud/alerts-reference
  2. https://learn.microsoft.com/en-us/azure/defender-for-cloud/defender-for-app-service-introduction
  3. https://azure.microsoft.com/en-us/services/app-service/
  4. https://learn.microsoft.com/en-us/azure/defender-for-cloud/plan-defender-for-servers
microsoft_antimalware_for_azure Microsoft Antimalware for Azure technique_scores T1027 Obfuscated Files or Information
Comments
This control can detect file obfuscation.
References
  1. https://learn.microsoft.com/en-us/azure/security/fundamentals/antimalware
  2. https://learn.microsoft.com/en-us/azure/security/fundamentals/antimalware-code-samples
microsoft_antimalware_for_azure Microsoft Antimalware for Azure technique_scores T1027 Obfuscated Files or Information
Comments
This control can prevent file obfuscation.
References
  1. https://learn.microsoft.com/en-us/azure/security/fundamentals/antimalware
  2. https://learn.microsoft.com/en-us/azure/security/fundamentals/antimalware-code-samples

GCP Mappings

Capability ID Capability Description Mapping Type ATT&CK ID ATT&CK Name Notes
google_secops Google Security Operations technique_scores T1027 Obfuscated Files or Information
Comments
Google Security Ops is able to trigger an alert based off suspicious command line arguments or processes that indicate obfuscation techniques to evade cyber defenses. For example, when cmd.exe has been obfuscated. This mapping was scored as minimal based on low or uncertain detection coverage factor of the technique. https://github.com/chronicle/detection-rules/blob/783e0e5947774785db1c55041b70176deeca6f46/soc_prime_rules/threat_hunting/windows/detect_cmd_exe_obfuscation.yaral https://github.com/chronicle/detection-rules/blob/783e0e5947774785db1c55041b70176deeca6f46/soc_prime_rules/threat_hunting/windows/ursnif_trojan_detection__cmd_obfuscation.yaral
References
  1. ['https://cloud.google.com/security/products/security-operations'
  2. 'https://cloud.google.com/chronicle/docs/secops/secops-overview'
  3. 'https://github.com/chronicle/detection-rules']

ATT&CK Subtechniques

Technique ID Technique Name Number of Mappings
T1027.011 Fileless Storage 5
T1027.009 Embedded Payloads 9
T1027.013 Encrypted/Encoded File 8
T1027.008 Stripped Payloads 6
T1027.001 Binary Padding 1
T1027.012 LNK Icon Smuggling 6
T1027.005 Indicator Removal from Tools 7
T1027.014 Polymorphic Code 7
T1027.003 Steganography 1
T1027.004 Compile After Delivery 3
T1027.006 HTML Smuggling 2
T1027.010 Command Obfuscation 12
T1027.002 Software Packing 7
T1027.007 Dynamic API Resolution 8