COMMON ATTACK PATTERN ENUMERATION AND CLASSIFICATIONLive MITRE record
CAPEC-692
Spoof Version Control System Commit Metadata
An adversary spoofs metadata pertaining to a Version Control System (VCS) (e.g., Git) repository's commits to deceive users into believing that the maliciously provided software is frequently maintained and originates from a trusted source.
Abstraction
Detailed
Typical severity
High
Likelihood of attack
Medium
Understand the attack
What is this attack pattern?
An adversary spoofs metadata pertaining to a Version Control System (VCS) (e.g., Git) repository's commits to deceive users into believing that the maliciously provided software is frequently maintained and originates from a trusted source.
Extended description
Version Control Systems are widely used by developers to host, track, and manage source code files in an easy and synchronous manner. These systems are often leveraged to host open-source software that other developers can incorporate into their own applications or use as standalone applications. To prevent downloading vulnerable and/or malicious code, developers will often check the metadata of VCS repository commits to determine the repository's overall pedigree. This may include a variety of information, such as the following:
Owner of the repository
Author(s) of commits
Frequency of commits
Date/Time of commits
Repository activity graphs
These precursory checks can assist developers in determining whether a trusted individual/organization is providing the source code, how often the code is updated, and the relative popularity of the software. However, an adversary can spoof this metadata to make a repository containing malicious code appear as originating from a trusted source, being frequently maintained, and being commonly used by other developers. Without performing additional security activities, unassuming developers may be duped by this spoofed metadata and include the malicious code within their systems/applications. The adversary is then ultimately able to achieve numerous negative technical impacts, while the victim remains unaware of any malicious activity.
Execution flow
How does the attack proceed, step by step?
Explore
Identify target
The adversary must first identify a target repository for them to spoof. Typically, this will be a popular and widely used repository, as to increase the amount of victims a successful attack will exploit.
Experiment
Create malicious repository
The adversary must create a malicious repository that imitates the legitimate repository being spoofed. This may include creating a username that closely matches the legitimate repository owner; creating a repository name that closely matches the legitimate repository name; uploading the legitimate source code; and more.
Spoof commit metadata
Once the malicious repository has been created, the adversary must then spoof the commit metadata to make the repository appear to be frequently maintained and originating from trusted sources.
Techniques used
- Git Commit Timestamps: The adversary generates numerous fake commits while setting the "GIT_AUTHOR_DATE" and "GIT_COMMITTER_DATE" environment variables to a date which is to be spoofed.
- Git Commit Contributors: The adversary obtains a legitimate and trusted user's email address and then sets this information via the "git config" command. The adversary can then commit changes leveraging this username.
Exploit
Exploit victims
The adversary infiltrates software and/or system environments with the goal of conducting additional attacks.
Techniques used
- Active: The adversary attempts to trick victims into downloading the malicious software by means such as phishing and social engineering.
- Passive: The adversary waits for victims to download and leverage malicious software.
Requirements
What does the attack require?
Prerequisites
- Identification of a popular open-source repository whose metadata is to be spoofed.
Skills required
- Medium: Ability to spoof a variety of repository metadata to convince victims the source is trusted.
Resources required
Not stated in the MITRE record.
Impact
What does a successful attack lead to?
Modify Data
Affected scopes: Integrity
Hide Activities
Affected scopes: Accountability
Execute Unauthorized CommandsAlter Execution LogicGain Privileges
Affected scopes: Access Control, Authorization
Defence
How is it prevented and mitigated?
1
Before downloading open-source software, perform precursory metadata checks to determine the author(s), frequency of updates, when the software was last updated, and if the software is widely leveraged.
2
Reference vulnerability databases to determine if the software contains known vulnerabilities.
3
Only download open-source software from reputable hosting sites or package managers.
4
Only download open-source software that has been adequately signed by the developer(s). For repository commits/tags, look for the "Verified" status and for developers leveraging "Vigilant Mode" (GitHub) or similar modes.
5
After downloading open-source software, ensure integrity values have not changed.
6
Before executing or incorporating the software, leverage automated testing techniques (e.g., static and dynamic analysis) to determine if the software behaves maliciously.
Real world
MITRE example instances
Example instance 1Detail
In July 2022, Checkmarx reported that GitHub commit metadata could be spoofed if unsigned commits were leveraged by the repository. Adversaries were able to spoof commit contributors, as well as the date/time of the commit. This resulted in commits appearing to originate from trusted developers and a GitHub activity graph that duped users into believing that the repository had been maintained for a significant period of time. The lack of commit metadata validation ultimately allowed adversaries to propagate malware to unsuspecting victims [ REF-719 ] [ REF-720 ].