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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®

CRI Profile Mappings

Capability ID Capability Description Mapping Type ATT&CK ID ATT&CK Name Notes
DE.AE-02.01 Event analysis and detection Mitigates T1027 Obfuscated Files or Information
Comments
This diagnostic statement provides for implementation of methods to block similar future attacks via security tools such as antivirus and IDS/IPS to provide protection against threats and exploitation attempts.
References
    PR.IR-01.08 End-user device access Mitigates T1027 Obfuscated Files or Information
    Comments
    This diagnostic statement implements technical controls (e.g., VPN, antivirus software) to address the risks of end-user personal computing devices accessing the organization’s network and resources.
    References
      PR.PS-05.01 Malware prevention Mitigates T1027 Obfuscated Files or Information
      Comments
      Antivirus/Antimalware software can be utilized to detect and quarantine suspicious files that adversaries have made difficult to discover by encrypting, encoding, or obfuscating.
      References
        PR.PS-01.01 Configuration baselines Mitigates T1027 Obfuscated Files or Information
        Comments
        This diagnostic statement provides for securely configuring production systems. This includes hardening default configurations and making security-focused setting adjustments to reduce the attack surface, enforce best practices, and protect sensitive data thereby mitigating adversary exploitation.
        References
          PR.PS-01.08 End-user device protection Mitigates T1027 Obfuscated Files or Information
          Comments
          This diagnostic statement protects against Obfuscated Files or Information through the use of limiting access to resources to only authorized devices, management of personal computing devices, network intrusion prevention, and the use of antimalware.
          References

            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
            microsoft_sentinel Microsoft Sentinel technique_scores T1027 Obfuscated Files or Information
            Comments
            The Microsoft Sentinel Analytics "Powershell Empire cmdlets seen in command line" query can detect the use of Empire, which can obfuscate commands using Invoke-Obfuscation, but does not address other procedures.
            References
            1. https://learn.microsoft.com/en-us/azure/sentinel/overview
            2. https://learn.microsoft.com/en-us/azure/sentinel/hunting
            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 14
            T1027.013 Encrypted/Encoded File 13
            T1027.008 Stripped Payloads 6
            T1027.001 Binary Padding 1
            T1027.012 LNK Icon Smuggling 10
            T1027.005 Indicator Removal from Tools 7
            T1027.014 Polymorphic Code 12
            T1027.003 Steganography 1
            T1027.004 Compile After Delivery 3
            T1027.006 HTML Smuggling 3
            T1027.010 Command Obfuscation 16
            T1027.002 Software Packing 12
            T1027.007 Dynamic API Resolution 8