Listen to this Post
Introduction:
In a concerning revelation, Vercel has uncovered additional compromised accounts, some predating the publicly acknowledged breach. Attackers orchestrated a multi-stage chain: initial malware infection led to Google Workspace takeover, followed by privilege escalation into Vercel environments where they mapped internal systems and decrypted environment variables. The abuse of OAuth trust relationships enabled seamless lateral movement across cloud tenants—highlighting a critical blind spot in identity‑centric security postures.
Learning Objectives:
- Understand the attack flow from endpoint malware to cloud infrastructure compromise.
- Learn to detect and block OAuth abuse and lateral movement using native logs and commands.
- Implement hardening controls for Vercel, Google Workspace, and environment variable encryption.
You Should Know:
- Anatomy of the Attack Chain: Malware → Workspace → Vercel
Attackers initially deploy malware (e.g., infostealers, session hijackers) on an employee’s workstation. Once inside, they harvest Google Workspace session tokens or primary credentials. With access to the victim’s Google Workspace, adversaries enumerate connected OAuth applications—specifically targeting Vercel’s integration. Because OAuth trust is often granted with scopes like openid, email, and project:read-all, attackers can impersonate the user, list Vercel projects, and decrypt environment variables stored server‑side.
Step‑by‑step guide to simulate detection (using a lab environment with consent):
1. Check for suspicious OAuth grants (Linux/macOS):
`gcloud oauth client list` (for Google Cloud) or use Google Workspace audit API.
2. Enumerate Vercel projects using stolen tokens (requires `vercel` CLI):
`vercel login` with the compromised Google account, then vercel project list.
3. Attempt to pull environment variables:
`vercel env pull .env.production` – if the token has sufficient permissions, secrets are exposed.
4. Linux command to review recent token access:
`grep -i “oauth\|token” /var/log/auth.log` and journalctl -u google-chrome --since "1 hour ago".
- Decrypting Environment Variables: How Attackers Exploit Vercel’s Encryption
Vercel encrypts environment variables at rest, but decryption keys are accessible to authenticated API calls with proper project roles. Attackers leverage OAuth tokens to call the Vercel API endpoint GET /v1/projects/{projectId}/env. No additional breaking of cryptography is required—the platform serves decrypted values to legitimate-looking requests.
Step‑by‑step extraction & hardening:
- Using `curl` to simulate attacker API call (replace with your token):
`curl -H “Authorization: Bearer $VERCEL_TOKEN” https://api.vercel.com/v9/projects/{projectId}/env`
2. Windows PowerShell version:
`$headers = @{ Authorization = “Bearer $env:VERCEL_TOKEN” }; Invoke-RestMethod -Uri “https://api.vercel.com/v9/projects/proj123/env” -Headers $headers`
3. Prevent exposure:
- Rotate all environment variables immediately after any OAuth revocation.
- Use Vercel’s “encrypted” + “sensitive” flags and enforce Preview environment only for high‑risk secrets.
- Migrate secrets to a dedicated vault (e.g., HashiCorp Vault) and inject them via CI/CD, never store directly as Vercel env vars.
3. Detecting OAuth Lateral Movement with Native Logs
Lateral movement arises when a single OAuth token grants access to multiple Google Workspace-connected apps. Attackers pivot from Google Drive to Vercel to Slack to AWS. You can detect this by correlating token issuance and resource access timestamps.
Step‑by‑step detection with Google Workspace & Vercel logs:
- Enable OAuth token audit logging in Google Admin:
Go to `Reporting → Audit → OAuth Token` and export logs to BigQuery. - Linux command to query recent OAuth usage (using `grep` and
awk):
`grep “OAuth2Assertion” /var/log/google_workspace_audit.log | awk ‘{print $4,$7,$9}’ | sort | uniq -c`
3. Windows: Use `Get-WinEvent` to filter for OAuth logins from unexpected IPs:
`Get-WinEvent -LogName Security | Where-Object { $_.Id -in 4624,4648 -and $_.Message -like “OAuth” } | Format-Table TimeCreated,IPAddress`
4. Write a simple Python script to check Vercel audit logs for environment variable fetches:
Use Vercel’s REST API with endpoint `/v1/events` – look for `env.read` events outside normal build times.
4. Hardening Google Workspace Against OAuth Token Theft
The attack succeeded because malware stole persistent tokens. To block this, enforce device posture checks and conditional access policies that invalidate tokens when risk signals change.
Step‑by‑step hardening configuration:
1. Google Workspace:
- Set session length to 7 days max, require re‑authentication for sensitive apps.
- Enable Context‑Aware Access → restrict Vercel OAuth to trusted IP ranges and compliant devices.
- Regularly review third‑party OAuth apps via
Admin → Security → API Controls → Manage Third‑Party App Access.
- Linux command to check for suspicious browser extensions that steal tokens:
`find ~/.config/google-chrome/Default/Extensions/ -name “manifest.json” -exec grep -H “permissions” {} \; | grep -E “cookies|tabs|webRequest”`
3. Windows PowerShell to list all OAuth grants for a specific user:
`Connect-MgGraph -Scopes “Application.Read.All”, “Policy.Read.All”` then `Get-MgUserOauth2PermissionGrant -UserId “[email protected]” | Format-Table ClientId,Scope` - Post‑Exploitation Forensics: Tracing Malware That Started It All
Assume the endpoint is patient zero. Isolate and collect artifacts showing malware that exported Google Workspace tokens.
Step‑by‑step forensics commands (run on suspected Linux or Windows endpoint):
1. Linux – find token files and recent process execution:
`find /home -name “token” -o -name “cookies” 2>/dev/null`
`lsof -i :443 | grep -E “google|vercel”`
- Windows – extract saved Chrome/Edge tokens (requires admin):
`cd “$env:LOCALAPPDATA\Google\Chrome\User Data\Default”`
`sqlite3 Cookies “SELECT host_key,name,value FROM cookies WHERE host_key LIKE ‘%google%’ OR host_key LIKE ‘%vercel%’;”`
3. Detect credential dumping tools:
`procdump -ma lsass.exe lsass.dmp` (investigative only) – look for Mimikatz or open-source stealers via `Get-FileHash` on known bad hashes.
6. Mitigating Environment Variable Exposure in CI/CD
Vercel is not alone; Netlify, AWS Amplify, and GitHub Actions suffer similar OAuth risks. Implement a zero‑trust secrets approach.
Step‑by‑step cloud hardening:
- Never store production secrets as plain environment variables – use a secrets manager (AWS Secrets Manager, Azure Key Vault, GCP Secret Manager). In Vercel, integrate with Vercel Secrets + external vault.
- Rotate all environment variables with a script (bash example):
for var in $(vercel env list production --plain); do new_val=$(openssl rand -base64 32) vercel env rm $var production --yes echo $new_val | vercel env add $var production done
- Enforce short‑lived OAuth tokens by setting `–token-expiry=1h` in Vercel CLI and forcing re‑grant on every deployment.
- Use Azure Conditional Access to block OAuth from non‑corporate devices:
PowerShell command to create policy:
`New-AzureADMSConditionalAccessPolicy -DisplayName “Block OAuth from unmanaged devices” -GrantControls $grantControls -Conditions $conditions`
7. Monitoring & Alerting for Similar Attacks
Implement real‑time detection for the exact tactics used.
Step‑by‑step using open‑source tools:
- Deploy osquery to audit OAuth token creation on endpoints:
`SELECT FROM osquery_events WHERE name = ‘oauth_token_generation’;`
- Use Falco rules to detect Vercel API calls from unexpected source IPs (Linux):
Rule: `- rule: Vercel API from non‑build IPs`
`condition: evt.type=connect and fd.sip=”vercel.com” and not fd.sip in (trusted_build_ips)`
3. Windows Event Log monitoring for OAuth sign‑ins (Event ID 4648 with LogonType 9):
`Get-WinEvent -FilterHashtable @{LogName=’Security’; ID=4648; Data=””OAuth””} | Where-Object {$_.Properties[bash].Value -like ‘Vercel’}`
What Undercode Say:
- Key Takeaway 1: OAuth trust is a double‑edged sword – it enables seamless integrations but also creates a perfect pivot path when user tokens are stolen via endpoint malware.
- Key Takeaway 2: Environment variable decryption is not “hacking” cryptography; it’s simply abusing legitimate API endpoints with a valid OAuth token – making secret rotation and short‑lived tokens non‑negotiable.
Analysis: The Vercel incident is a stark reminder that cloud providers inherit identity risks from adjacent ecosystems (Google Workspace). The attack chain is alarmingly simple: malware → token → OAuth trust → decrypted secrets → lateral movement. Defenders must stop treating OAuth as “background plumbing” and start auditing third‑party apps, enforcing device compliance, and assuming every token can be stolen. The real lesson: no amount of server‑side encryption matters if the decryption key is handed to an authenticated attacker. Expect copycat attacks targeting Netlify, Railway, and any PaaS with OAuth‑driven environment variable management.
Prediction:
Within 12 months, we will see a surge of “OAuth pivot” attacks targeting CI/CD platforms. Attackers will automate the discovery of connected apps via workspace enumeration tools, then exfiltrate environment variables to compromise production databases and cloud storage. Defenders will respond by mandating short-lived OAuth tokens (≤1 hour) and implementing runtime secret injection from external vaults, effectively removing static environment variables from PaaS dashboards. The era of “set and forget” cloud secrets is ending.
▶️ Related Video (82% Match):
https://www.youtube.com/watch?v=7JjFjk4oCq4
🎯Let’s Practice For Free:
IT/Security Reporter URL:
Reported By: Hackermohitkumar Vercel – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
