CVE-2017-7239
📋 TL;DR
CVE-2017-7239 is a critical vulnerability in Ninka license scanner versions before 1.3.2 that allows remote attackers to execute arbitrary code, manipulate license compliance results, or cause denial of service via specially crafted filenames. This affects organizations using Ninka for open source license compliance scanning. The vulnerability stems from improper input validation (CWE-74) that enables injection attacks.
💻 Affected Systems
- Ninka
📦 What is this software?
Ninka by Ninka Project
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution with full system compromise, allowing attackers to steal sensitive data, manipulate license compliance reports, or disrupt scanning operations.
Likely Case
Denial of service causing Ninka processes to hang, disrupting license compliance workflows and potentially affecting automated build pipelines.
If Mitigated
Limited impact with proper network segmentation and input validation, though some service disruption may still occur.
🎯 Exploit Status
Exploitation requires only the ability to provide a crafted filename to Ninka, which can be achieved through various vectors including malicious repositories, build artifacts, or file uploads.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 1.3.2
Vendor Advisory: https://github.com/dmgerman/ninka/commit/81f185261c8863c5b84344ee31192870be939faf
Restart Required: No
Instructions:
1. Stop any running Ninka processes. 2. Update Ninka to version 1.3.2 or later using your package manager or from GitHub. 3. Verify the update completed successfully. 4. Resume normal operations.
🔧 Temporary Workarounds
Input validation wrapper
linuxCreate a wrapper script that validates filenames before passing to Ninka
#!/bin/bash
# Validate filename doesn't contain dangerous characters
if [[ "$1" =~ [\|;&$`] ]]; then
echo "Invalid filename detected"
exit 1
fi
# Run Ninka with validated input
ninka "$1"
Sandbox execution
allRun Ninka in a container or sandbox with limited permissions
docker run --rm -v $(pwd):/scan ninka:1.3.2 /scan/filename
🧯 If You Can't Patch
- Isolate Ninka to a dedicated scanning environment with no network access to production systems
- Implement strict input validation for all filenames processed by Ninka, rejecting any containing special characters
🔍 How to Verify
Check if Vulnerable:
Check Ninka version: ninka --version | grep -q '1\.3\.[01]\|1\.[0-2]\|0\.' && echo 'VULNERABLE'Check Version:
ninka --versionVerify Fix Applied:
Run: ninka --version | grep -q '1\.3\.2\|[2-9]\|1\.[4-9]' && echo 'PATCHED'📡 Detection & Monitoring
Log Indicators:
- Ninka process hanging indefinitely
- Unexpected system calls from Ninka process
- License scan results showing manipulation
Network Indicators:
- Unusual outbound connections from Ninka host
- Large volume of failed scan attempts
SIEM Query:
process_name:"ninka" AND (event_type:"process_hang" OR cmdline:"*[special chars]*")🔗 References
- http://www.openwall.com/lists/oss-security/2017/04/03/3
- http://www.securityfocus.com/bid/97325
- https://github.com/dmgerman/ninka/commit/81f185261c8863c5b84344ee31192870be939faf
- http://www.openwall.com/lists/oss-security/2017/04/03/3
- http://www.securityfocus.com/bid/97325
- https://github.com/dmgerman/ninka/commit/81f185261c8863c5b84344ee31192870be939faf
