Listen to this Post
Introduction
In a sophisticated supply chain attack, malicious actors compromised an SAP developer’s laptop, leveraged an already‑authorized Code GitHub integration, and pushed trojanized versions of popular SAP CAP framework npm packages—including @cap-js/sqlite, @cap-js/postgres, @cap-js/cds-dbs, and @sap/cloud-mta-build-tool. The attacker minted npm tokens via OIDC and double‑base64 encoded them into CI logs, highlighting a dangerous new vector where AI agents become unintended identities in your repositories.
Learning Objectives
- Understand how a compromised developer laptop combined with an authorized AI agent ( Code) enabled an npm supply chain attack.
- Learn to detect and mitigate OIDC token abuse and double‑base64 exfiltration in CI/CD pipelines.
- Implement hardening measures for AI tool integrations, cloud workload identity, and npm package security.
You Should Know
- The Attack Chain: From Dev Laptop to Trojanized npm Packages
The attacker didn’t steal an npm token directly. Instead, they infected an SAP developer’s machine, discovered that Code’s GitHub integration was already authorized, and used that trusted identity to push a malicious commit to the official `cap-js/cds-dbs` repository. The commit—disguised as "ci: fix"—contained a minimal but devastating diff:
OIDC_TOKEN=$(curl ... audience=npm:registry.npmjs.org) NPM_TOKEN=$(curl ... oidc/token/exchange/package/%40cap-js%2Fsqlite) echo $NPM_TOKEN | base64 -w 0 | base64 -w 0
Step‑by‑step what this does:
- Requests an OIDC token from the cloud provider (likely GitHub Actions or similar) with audience set to
npm:registry.npmjs.org. - Exchanges that OIDC token for a scoped npm publish token via npm’s OIDC token exchange endpoint.
- Double‑base64 encodes the resulting npm token and prints it to the CI log, where the attacker could retrieve it.
The trojanized packages were live on npm between 11:25–14:00 UTC. Any CI pipeline or developer who pulled those packages during that window is compromised.
Verify affected packages on Linux/macOS:
npm list @cap-js/sqlite @cap-js/postgres @cap-js/cds-dbs @sap/cloud-mta-build-tool --depth=0
On Windows (PowerShell):
npm list @cap-js/sqlite @cap-js/postgres @cap-js/cds-dbs @sap/cloud-mta-build-tool --depth=0
- Technical Deep Dive: OIDC Token Exchange and Double‑Base64 Exfiltration
OIDC (OpenID Connect) allows CI platforms to exchange a trusted identity for a short‑lived npm token without storing long‑lived secrets. The attacker abused this by:
– Using the audience parameter to restrict the token to npm’s registry.
– Calling the npm OIDC exchange endpoint for the specific package.
– Double‑base64 encoding to evade simple log scanning (e.g., echo $TOKEN | base64 -w 0 | base64 -w 0).
Decode a suspicious double‑base64 value (Linux/macOS):
echo "suspicious_base64_string" | base64 -d | base64 -d
Check CI logs for base64 patterns (grep):
grep -E '[A-Za-z0-9+/]{40,}={0,2}' ci-build.log
grep -E 'base64.base64' ci-build.log
Monitor npm OIDC token exchanges in cloud audit logs (AWS CloudTrail example):
{
"eventName": "AssumeRoleWithWebIdentity",
"requestParameters": {"audience": "npm:registry.npmjs.org"}
}
3. Immediate Response: Rotating Compromised Credentials and Packages
If you pulled any affected package during the window, treat every credential accessible from that environment as exposed.
Step‑by‑step response plan:
1. Identify installed versions of the trojanized packages:
npm ls | grep -E "@cap-js/(sqlite|postgres|cds-dbs)|@sap/cloud-mta-build-tool"
2. Remove the packages and any suspicious post‑install scripts:
npm uninstall @cap-js/sqlite @cap-js/postgres @cap-js/cds-dbs @sap/cloud-mta-build-tool rm -rf node_modules package-lock.json && npm install
3. Rotate all cloud provider tokens (AWS, Azure, GCP) that were used in the same environment:
– AWS: `aws sts revoke-oauth-token` or rotate IAM keys via console/CLI.
– Azure: `az ad app credential reset –id
– GCP: `gcloud iam service-accounts keys revoke
4. Revoke GitHub Personal Access Tokens (PATs) and regenerate:
– GitHub → Settings → Developer settings → Personal access tokens → Delete and recreate.
5. Delete and recreate `..json` and any MCP (Model Context Protocol) config files that contained session tokens.
6. Rotate any environment variables that might have been logged during CI runs.
- Hardening AI Agent Integrations: Least Privilege for Code and MCP
Your AI agent is now an identity in your repos—treat it like your most sensitive service account.
Step‑by‑step to secure Code integration:
- Use fine‑grained GitHub PATs for Code, not classic tokens:
– Repository access: Only specific repos needed for the task.
– Permissions: `contents: read` (disable write unless explicitly required).
– Never use tokens with `repo` or `workflow` scopes without strict justification.
2. Isolate AI agent authorizations to short‑lived, single‑use tokens:
Generate a token that expires in 1 hour via GitHub CLI gh auth token --scopes repo --expires-in 3600
3. Restrict commit signing – AI agents should not push code directly. Use PR workflows with human review.
4. Audit `..json` and MCP credentials:
Linux: find any config files find ~ -name "..json" -o -name "mcp_config.json" Windows (PowerShell) Get-ChildItem -Path C:\Users\ -Recurse -Include ..json, mcp_config.json -ErrorAction SilentlyContinue
5. Enable GitHub’s IP allow lists for CI and developer environments used by AI tools.
- Detecting Similar Attacks: CI Log Monitoring and OIDC Anomalies
The attack printed the double‑base64 token directly into CI logs. You can build detection rules around this behavior.
SIEM rule example (Splunk/Elastic):
index=ci_logs
("base64 -w 0" OR "base64 --wrap=0") AND ("curl" AND "oidc/token/exchange")
Linux command to scan historical logs:
sudo grep -rnw '/var/log/' -e 'base64 -w 0' -e 'oidc/token/exchange' --color=always
Monitor npm OIDC exchange API calls via proxy logs:
Check for unusual audience parameters
jq 'select(.request.url | contains("oidc/token/exchange")) | .request.body' /var/log/nginx/access.log
Proactive detection:
- Use `npm audit` to detect published malicious packages:
npm audit --json | jq '.advisories[] | select(.title | contains("trojan"))' - Enable GitHub’s dependency submission API to receive real‑time alerts.
- Mitigation and Long‑Term Protection: npm Security Best Practices
Step‑by‑step to harden your npm usage:
- Use npm provenance – requires publish provenance statements to verify package origin:
npm publish --provenance
2. Ignore post‑install scripts in CI environments:
npm install --ignore-scripts Or globally disable scripts npm config set ignore-scripts true
3. Pin dependencies with integrity hashes in `package-lock.json` – run `npm ci` instead of `npm install` in CI.
4. Use a private npm registry or caching proxy (e.g., Verdaccio, JFrog Artifactory) to vet packages before internal use.
5. Enable package signing verification with `npm sign` (requires npm@9+):
npm sign --package @cap-js/sqlite@version
6. Rotate npm tokens regularly and enforce short expiry (max 30 days):
npm token create --cidr=192.168.0.0/24 --readonly npm token revoke <token-id>
- Cloud and API Security Lessons: Hardening OIDC Workload Identity
The attack succeeded because the OIDC flow lacked additional constraints beyond audience. Implement defense‑in‑depth:
Step‑by‑step to secure OIDC token exchange:
- Restrict OIDC audience to exact registry – in GitHub Actions:
permissions: id-token: write env: NPM_AUDIENCE: npm:registry.npmjs.org
- Add conditional claims – require a specific `repository` claim to exchange tokens:
with: workload-identity-provider: projects/123/locations/global/workloadIdentityPools/my-pool/providers/github service-account: [email protected] condition: "attribute.repository_owner=='cap-js'"
- Never print exchanged tokens to logs – enforce log redaction in CI:
– GitHub Actions: `::add-mask::${NPM_TOKEN}`
– GitLab CI: `masked: true` in variable definition.
4. Use short‑lived npm tokens (24‑hour expiry) exchanged every CI run rather than reusing tokens.
Verify your cloud OIDC configuration (AWS CLI):
aws iam list-open-id-connect-providers aws iam get-open-id-connect-provider --open-id-connect-provider-arn <arn>
What Undercode Say
- AI agents are now privileged identities – Authorizing Code or any AI tool grants commit and token‑exchange capabilities. Treat them as you would a human developer with admin rights.
- Compromised dev laptop + AI trust = perfect supply chain vector – The attack didn’t need sophisticated zero‑days. It abused existing trust relationships and weak OIDC validation.
- Double‑base64 encoding is a simple but effective evasion – Many log scanners only decode once. Always recursively decode potential secrets.
- npm OIDC token exchange should never be silent – Implement real‑time alerting for any exchange targeting high‑value packages, and enforce IP allowlisting.
- You must rotate everything, not just npm – The attacker could have pivoted from npm tokens to cloud metadata endpoints, GitHub PATs, or even MCP configs stored on the developer’s laptop.
The incident underscores a fundamental shift: as AI agents gain write access to your repos and CI pipelines, they become prime targets. Traditional token rotation and static secret management are no longer sufficient. Organizations must adopt ephemeral, workload‑specific tokens, enforce strict least privilege on AI integrations, and continuously monitor for anomalous OIDC exchanges. The attack on SAP CAP is a wake‑up call to treat every identity—human, machine, or AI—as potentially compromised.
Prediction
Within the next 12 months, supply chain attacks targeting AI‑agent integrations ( Code, GitHub Copilot, MCP) will increase by 300%. Attackers will shift from stealing developer tokens to compromising the AI agents themselves, using them as unwitting proxies to inject malicious code into repositories. We predict that npm, PyPI, and other registries will enforce mandatory OIDC audience locking and short‑lived (≤1 hour) token lifetimes. Cloud providers will introduce AI‑agent‑specific identity types with built‑in logging and behavior analysis. Organizations that fail to isolate AI tooling into dedicated, read‑only environments will suffer similar trojanization events. The SAP CAP attack is not an anomaly—it is the blueprint for the next generation of software supply chain compromise.
▶️ Related Video (70% Match):
🎯Let’s Practice For Free:
IT/Security Reporter URL:
Reported By: Dean Bar – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
