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Masquerading: Invalid Code Signature

ID Name
T1036.001 Invalid Code Signature
T1036.002 Right-to-Left Override
T1036.003 Rename System Utilities
T1036.004 Masquerade Task or Service
T1036.005 Match Legitimate Name or Location
T1036.006 Space after Filename
T1036.007 Double File Extension
T1036.008 Masquerade File Type
T1036.009 Break Process Trees
T1036.010 Masquerade Account Name

Adversaries may attempt to mimic features of valid code signatures to increase the chance of deceiving a user, analyst, or tool. Code signing provides a level of authenticity on a binary from the developer and a guarantee that the binary has not been tampered with. Adversaries can copy the metadata and signature information from a signed program, then use it as a template for an unsigned program. Files with invalid code signatures will fail digital signature validation checks, but they may appear more legitimate to users and security tools may improperly handle these files.[1]

Unlike Code Signing, this activity will not result in a valid signature.

ID: T1036.001
Sub-technique of:  T1036
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Tactic: Defense Evasion
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Platforms: Windows, macOS
Version: 1.0
Created: 10 February 2020
Last Modified: 10 February 2020
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Procedure Examples

ID Name Description
G0067 APT37

APT37 has signed its malware with an invalid digital certificates listed as "Tencent Technology (Shenzhen) Company Limited."[2]
S0128 BADNEWS

BADNEWS is sometimes signed with an invalid Authenticode certificate in an apparent effort to make it look more legitimate.[3]
S0666 Gelsemium

Gelsemium has used unverified signatures on malicious DLLs.[4]
S0198 NETWIRE

The NETWIRE client has been signed by fake and invalid digital certificates.[5]
S1050 PcShare

PcShare has used an invalid certificate in attempt to appear legitimate.[6]
S0019 Regin

Regin stage 1 modules for 64-bit systems have been found to be signed with fake certificates masquerading as originating from Microsoft Corporation and Broadcom Corporation.[7]
G0112 Windshift

Windshift has used revoked certificates to sign malware.[8][9]
S0466 WindTail

WindTail has been incompletely signed with revoked certificates.[8]

Mitigations

ID Mitigation Description
M1045 Code Signing

Require signed binaries.

Detection

ID Data Source Data Component Detects
DS0022 File File Metadata

Collect and analyze signing certificate metadata and check signature validity on software that executes within the environment, look for invalid signatures as well as unusual certificate characteristics and outliers.

References

  1. Vest, J. (2017, October 9). Borrowing Microsoft MetaData and Signatures to Hide Binary Payloads. Retrieved September 10, 2019.
  2. Raiu, C., and Ivanov, A. (2016, June 17). Operation Daybreak. Retrieved February 15, 2018.
  3. Lunghi, D., et al. (2017, December). Untangling the Patchwork Cyberespionage Group. Retrieved July 10, 2018.
  4. Dupuy, T. and Faou, M. (2021, June). Gelsemium. Retrieved November 30, 2021.
  5. McAfee. (2015, March 2). Netwire RAT Behind Recent Targeted Attacks. Retrieved February 15, 2018.
  1. Vrabie, V. (2020, November). Dissecting a Chinese APT Targeting South Eastern Asian Government Institutions. Retrieved September 19, 2022.
  2. Kaspersky Lab's Global Research and Analysis Team. (2014, November 24). THE REGIN PLATFORM NATION-STATE OWNAGE OF GSM NETWORKS. Retrieved December 1, 2014.
  3. Wardle, Patrick. (2018, December 20). Middle East Cyber-Espionage analyzing WindShift's implant: OSX.WindTail (part 1). Retrieved October 3, 2019.
  4. Karim, T. (2018, August). TRAILS OF WINDSHIFT. Retrieved June 25, 2020.