AWS - CodeBuild Post Exploitation
CodeBuild
For more information, check:
pageAWS - Codebuild EnumAbuse CodeBuild Repo Access
In order to configure CodeBuild, it will need access to the code repo that it's going to be using. Several platforms could be hosting this code:
The CodeBuild project must have access to the configured source provider, either via IAM role of with a github/bitbucket token or OAuth access.
An attacker with elevated permissions in over a CodeBuild could abuse this configured access to leak the code of the configured repo and others where the set creds have access. In order to do this, an attacker would just need to change the repository URL to each repo the config credentials have access (note that the aws web will list all of them for you):
And change the Buildspec commands to exfiltrate each repo.
However, this task is repetitive and tedious and if a github token was configured with write permissions, an attacker won't be able to (ab)use those permissions as he doesn't have access to the token. Or does he? Check the next section
Leaking Access Tokens from AWS CodeBuild
You can leak access given in CodeBuild to platforms like Github. Check if any access to external platforms was given with:
codebuild:DeleteProject
codebuild:DeleteProject
An attacker could delete an entire CodeBuild project, causing loss of project configuration and impacting applications relying on the project.
Potential Impact: Loss of project configuration and service disruption for applications using the deleted project.
codebuild:TagResource
, codebuild:UntagResource
codebuild:TagResource
, codebuild:UntagResource
An attacker could add, modify, or remove tags from CodeBuild resources, disrupting your organization's cost allocation, resource tracking, and access control policies based on tags.
Potential Impact: Disruption of cost allocation, resource tracking, and tag-based access control policies.
codebuild:DeleteSourceCredentials
codebuild:DeleteSourceCredentials
An attacker could delete source credentials for a Git repository, impacting the normal functioning of applications relying on the repository.
Potential Impact: Disruption of normal functioning for applications relying on the affected repository due to the removal of source credentials.
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