# AWS - CodeBuild Post Exploitation

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## CodeBuild

For more information, check:

{{#ref}}
../../aws-services/aws-codebuild-enum.md
{{#endref}}

### Check Secrets

If credentials have been set in Codebuild to connect to Github, Gitlab or Bitbucket in the form of personal tokens, passwords or OAuth token access, these **credentials are going to be stored as secrets in the secret manager**.\
Therefore, if you have access to read the secret manager you will be able to get these secrets and pivot to the connected platform.

{{#ref}}
../../aws-privilege-escalation/aws-secrets-manager-privesc/README.md
{{#endref}}

### Abuse 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:

<figure><img src="../../../../images/image (96).png" alt=""><figcaption></figcaption></figure>

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):

<figure><img src="../../../../images/image (107).png" alt=""><figcaption></figcaption></figure>

And **change the Buildspec commands to exfiltrate each repo**.

> [!WARNING]
> 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:

```bash
aws codebuild list-source-credentials
```

{{#ref}}
aws-codebuild-token-leakage.md
{{#endref}}

### Untrusted PR execution via webhook filter misconfiguration

If webhook filters are weak, external attackers can get their PRs built in privileged CodeBuild projects and then execute arbitrary code in CI.

{{#ref}}
aws-codebuild-untrusted-pr-webhook-bypass.md
{{#endref}}

### `codebuild:DeleteProject`

An attacker could delete an entire CodeBuild project, causing loss of project configuration and impacting applications relying on the project.

```bash
aws codebuild delete-project --name <value>
```

**Potential Impact**: Loss of project configuration and service disruption for applications using the deleted project.

### `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.

```bash
aws codebuild tag-resource --resource-arn <value> --tags <value>
aws codebuild untag-resource --resource-arn <value> --tag-keys <value>
```

**Potential Impact**: Disruption of cost allocation, resource tracking, and tag-based access control policies.

### `codebuild:DeleteSourceCredentials`

An attacker could delete source credentials for a Git repository, impacting the normal functioning of applications relying on the repository.

```sql
aws codebuild delete-source-credentials --arn <value>
```

**Potential Impact**: Disruption of normal functioning for applications relying on the affected repository due to the removal of source credentials.

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