Jenkins Plugin Flaw Exposes Stored Credentials: What Indian SMBs Must

Originally reported by NIST NVD (CVE-2023-24435)

Last week, I was reviewing security logs from one of our Bachao.AI customers—a mid-sized fintech startup in Bangalore—when I noticed something that made me pause. Their Jenkins instance had the vulnerable GitHub Pull Request Builder Plugin still running. They had no idea that anyone with basic read access could potentially drain their stored credentials. This incident perfectly illustrates why I started Bachao.AI: these vulnerabilities exist in the tools we trust, and most Indian SMBs simply don't have the resources to track them all.

Today, I want to walk you through CVE-2023-24435, why it matters for your business, and exactly what you need to do right now.

What Happened

In February 2023, a critical vulnerability was discovered in Jenkins GitHub Pull Request Builder Plugin version 1.42.2 and earlier. The flaw is deceptively simple: the plugin fails to properly check user permissions before allowing credential connections.

Here's the attack scenario:

An attacker with Overall/Read permission (the lowest privilege level in Jenkins) can exploit a missing permission check to:

1. Connect to any attacker-specified URL
2. Use attacker-specified credential IDs that were previously stored in Jenkins
3. Exfiltrate those credentials or use them to pivot to other systems

The vulnerability affects Jenkins instances where:

1. GitHub Pull Request Builder Plugin version 1.42.2 or earlier is installed
2. Users have been granted Overall/Read permission (common in collaborative environments)
3. Credentials are stored in Jenkins (nearly universal for CI/CD pipelines)

Why This Matters for Indian Businesses

In my years building enterprise systems, I've seen this pattern repeat: vulnerabilities in development tools get overlooked because they're not "user-facing." But for Indian SMBs, this is particularly dangerous.

The DPDP Act Connection

India's Digital Personal Data Protection (DPDP) Act 2023 now requires businesses to implement reasonable security measures to protect personal data. If your Jenkins instance gets compromised through this vulnerability and customer data is exfiltrated, you're not just dealing with a technical incident—you're facing potential regulatory action.

Under DPDP:

1. You must notify CERT-In within 6 hours of discovering a data breach
2. You must notify affected individuals without unreasonable delay
3. Failure to implement "reasonable security measures" can result in penalties up to Rs 5 crore (for larger breaches)

CERT-In's Perspective

CERT-In (the Indian Computer Emergency Response Team) has explicitly called out CI/CD pipeline vulnerabilities as a growing attack vector. Jenkins is used by thousands of Indian companies—from startups to enterprises—and a single compromised instance can give attackers access to:

1. Source code repositories
2. Deployment credentials
3. Production environment access
4. Customer databases

Real-World Impact for Indian SMBs

Let's be concrete. Imagine you're a SaaS company in Pune with 50 employees:

1. Your Jenkins instance stores AWS credentials for production
2. You have 30 developers with read access
3. One developer's account gets compromised (phishing, weak password, etc.)
4. That attacker now has Overall/Read permission and can exploit CVE-2023-24435
5. Within hours, your AWS credentials are stolen
6. Your production database is accessible
7. Customer data (protected under DPDP) is at risk
8. You now have a mandatory 6-hour window to notify CERT-In
9. RBI (if you handle financial data) and SEBI (if you're regulated) get involved
10. Your reputation is damaged, and you're facing regulatory fines

Technical Breakdown

Let me explain exactly how this vulnerability works:

The Attack Flow

graph TD
    A[Attacker with Overall/Read Permission] -->|Step 1: Access Jenkins UI| B[Navigate to GitHub PR Builder Config]
    B -->|Step 2: Missing Permission Check| C[View Stored Credential IDs]
    C -->|Step 3: Specify Attacker URL| D[Configure New PR Builder Job]
    D -->|Step 4: Trigger Job| E[Jenkins Connects to Attacker URL]
    E -->|Step 5: Credential Exfiltration| F[Attacker Captures Credentials]
    F -->|Step 6: Lateral Movement| G[Access Protected Resources]

Why This Happens

The GitHub Pull Request Builder Plugin stores credentials in Jenkins' credential store. When a job runs, it retrieves these credentials and uses them to authenticate with GitHub.

The vulnerability exists because the plugin doesn't verify that the user requesting the credential connection has permission to use those specific credentials. It only checks if they have Overall/Read permission (which is meant for viewing, not using credentials).

In code terms, it's like this:

// VULNERABLE CODE (simplified)
public class GitHubPRBuilder {
    public void connectToURL(String url, String credentialId) {
        // Missing: Permission check for credential usage
        // Only checks Overall/Read permission
        if (user.hasPermission("Overall/Read")) {
            Credential cred = credentialStore.get(credentialId);
            // Use credential to connect to attacker-specified URL
            connect(url, cred);
        }
    }
}

What it should do:

// FIXED CODE (simplified)
public class GitHubPRBuilder {
    public void connectToURL(String url, String credentialId) {
        // Verify user has permission to USE this specific credential
        if (!user.hasPermission("Credential/Use", credentialId)) {
            throw new AuthorizationException("Not permitted");
        }
        // Also validate the URL against a whitelist
        if (!isWhitelistedURL(url)) {
            throw new SecurityException("URL not allowed");
        }
        Credential cred = credentialStore.get(credentialId);
        connect(url, cred);
    }
}

Attack Prerequisites

For this attack to work, the attacker needs:

1. Overall/Read permission on the Jenkins instance (or the ability to gain it)
2. Knowledge of credential IDs (these are often visible in Jenkins UI or logs)
3. An attacker-controlled URL to exfiltrate credentials to
4. The vulnerable plugin version (1.42.2 or earlier)

How to Protect Your Business

If you're running Jenkins with the GitHub Pull Request Builder Plugin, here's your action plan:

Immediate Actions (Do Today)

1. Check Your Plugin Version

SSH into your Jenkins server and run:

# Check installed plugins
cd /var/lib/jenkins/plugins
ls -la | grep github-pullrequest

# Or check via Jenkins CLI
java -jar jenkins-cli.jar -s http://localhost:8080 list-plugins | grep github-pullrequest

If you see a version 1.42.2 or earlier, you're vulnerable.

2. Update the Plugin Immediately

# Via Jenkins UI: Manage Jenkins → Manage Plugins → Updates
# Check for "GitHub Pull Request Builder" and click "Download now and install after restart"

# Or via CLI:
java -jar jenkins-cli.jar -s http://localhost:8080 install-plugin github-pullrequest

Important: Test in a staging environment first, then restart Jenkins:

sudo systemctl restart jenkins
# Wait for Jenkins to fully start
sudo journalctl -u jenkins -f  # Monitor logs

3. Audit Credential Usage

Check who has accessed your stored credentials:

# Check Jenkins audit logs
cd /var/lib/jenkins
grep -r "credentialId" logs/ | head -20

# Check recent job executions
cd /var/lib/jenkins/jobs
find . -name "build.log" -exec grep -l "credential" {} \;

Short-Term Fixes (This Week)

4. Implement Least Privilege Access

Review who has Overall/Read permission:

# Via Jenkins UI: Manage Jenkins → Manage Users → Configure Global Security
# Reduce Overall/Read permission to only those who truly need it

Best practice:

1. Overall/Read: Only senior developers and DevOps engineers
2. Job/Read: Regular developers (for viewing builds)
3. Credential/Use: Only service accounts that actually need credentials

5. Rotate All Stored Credentials

Assuming your Jenkins instance might have been compromised:

# List all credentials
java -jar jenkins-cli.jar -s http://localhost:8080 list-credentials

# For each credential:
# 1. Generate a new token/key in the source system (GitHub, AWS, etc.)
# 2. Update it in Jenkins
# 3. Revoke the old credential

Example for GitHub:

# 1. Go to GitHub Settings → Developer settings → Personal access tokens
# 2. Create a new token with the same scopes
# 3. Update Jenkins: Manage Jenkins → Manage Credentials → Update
# 4. Delete the old token from GitHub

6. Enable Jenkins Audit Logging

Add this to your Jenkins configuration (/var/lib/jenkins/jenkins.model.JenkinsLocationConfiguration.xml):

<hudson.security.csrf.DefaultCrumbIssuer>
    <excludeClientIPFromCrumb>true</excludeClientIPFromCrumb>
</hudson.security.csrf.DefaultCrumbIssuer>

Enable detailed logging:

# Via Jenkins UI: Manage Jenkins → System Log → Add new log recorder
# Logger name: hudson.security
# Log level: FINE

Long-Term Strategy (This Month)

7. Implement a Secrets Management Solution

Stop storing credentials directly in Jenkins. Use a dedicated secrets vault:

Option 1: HashiCorp Vault (recommended for enterprises)

# Install Vault plugin in Jenkins
# Configure Jenkins to retrieve credentials from Vault
# Benefits: Centralized audit logs, automatic rotation, encryption

Option 2: AWS Secrets Manager (if you're on AWS)

# Install AWS Secrets Manager plugin
# Store credentials in AWS Secrets Manager
# Jenkins retrieves them at runtime

Option 3: Jenkins Credentials Binding (lightweight)

// In your Jenkinsfile
pipeline {
    agent any
    environment {
        AWS_CREDS = credentials('aws-credentials-id')
    }
    stages {
        stage('Deploy') {
            steps {
                sh 'aws s3 ls'  // Credentials are injected only at runtime
            }
        }
    }
}

8. Regular Security Audits

Schedule monthly reviews:

#!/bin/bash
# audit-jenkins.sh

echo "=== Jenkins Security Audit ==="
echo "\n1. Plugin Versions:"
java -jar jenkins-cli.jar -s http://localhost:8080 list-plugins | grep -E "github|security|auth"

echo "\n2. User Permissions:"
java -jar jenkins-cli.jar -s http://localhost:8080 list-credentials

echo "\n3. Recent Failed Logins:"
grep "Failed to authenticate" /var/lib/jenkins/logs/jenkins.log | tail -10

echo "\n4. Job Configurations with Credentials:"
grep -r "credentialId" /var/lib/jenkins/jobs/ | wc -l

Run this monthly:

chmod +x audit-jenkins.sh
./audit-jenkins.sh > jenkins-audit-$(date +%Y%m%d).log

How Bachao.AI Would Have Prevented This

This is exactly the type of vulnerability we're designed to catch. Here's how:

VAPT Scan — Vulnerability Assessment & Penetration Testing

1. How it helps: Our automated VAPT scanner would identify the outdated GitHub Pull Request Builder Plugin version
2. Detection method: We scan your Jenkins instance (with permission) and check all installed plugins against known CVE databases
3. What you get: Detailed report showing:

1. Cost: Free scan to identify issues; comprehensive report from Rs 1,999
2. Time to detect: Immediate (within minutes of scan)

Cloud Security — Jenkins-Specific Hardening

1. How it helps: If your Jenkins runs on AWS/GCP/Azure, we audit your CI/CD pipeline configuration
2. Detection method: We check:

1. What you get: Actionable hardening guide specific to your cloud setup
2. Cost: Starting at Rs 2,999 for cloud security audit
3. Time to detect: 2-3 hours for comprehensive audit

Incident Response — If You've Been Compromised

1. How it helps: Our 24/7 incident response team can help you:

1. Cost: Incident response packages from Rs 9,999
2. Time to respond: We're on-call 24/7; average response time is 15 minutes

Why This Matters

When I was architecting security for large enterprises, we had dedicated teams monitoring each system. Indian SMBs don't have that luxury. That's why Bachao.AI automates these checks:

1. Continuous monitoring: We track CVE databases daily so you don't have to
2. Indian compliance focus: We map vulnerabilities to DPDP Act, CERT-In requirements, and RBI guidelines
3. Affordable: No need for a full security team—pay only for what you use
4. Fast remediation: Get actionable steps, not just alerts

Action Items Checklist

Here's what you should do today:

1. [ ] Check if you have GitHub Pull Request Builder Plugin installed
2. [ ] Verify your plugin version (vulnerable if ≤ 1.42.2)
3. [ ] Update the plugin to the latest version
4. [ ] Audit who has Overall/Read permission
5. [ ] Rotate all stored credentials
6. [ ] Enable Jenkins audit logging
7. [ ] Book a free VAPT scan with Bachao.AI to check for other vulnerabilities
8. [ ] Schedule a monthly Jenkins security audit

Final Thoughts

CVE-2023-24435 is a perfect example of why SMBs need continuous security monitoring. It's not a flashy zero-day or a sophisticated attack—it's a simple authorization bypass in a tool you probably already use. And that's exactly what makes it dangerous.

The good news? It's completely preventable with the right practices and tools.

If you're unsure whether your Jenkins instance is secure, don't wait. Book a free VAPT scan today. We'll identify this and dozens of other vulnerabilities in your infrastructure, and give you a clear roadmap to fix them.

Stay secure,

Shouvik Mukherjee Founder & CEO, Bachao.AI

This article was researched and written by the Bachao.AI security team. We analyze cybersecurity incidents daily to help Indian businesses stay protected. Book a free security scan to check your exposure to CVE-2023-24435 and other vulnerabilities.

Have you experienced a Jenkins security incident? Share your story (anonymously) in the comments—it helps other SMBs learn.

Written by Shouvik Mukherjee, Founder & CEO of Bachao.AI. Follow me on LinkedIn for daily cybersecurity insights for Indian businesses.