CVE-2023-6746
📋 TL;DR
CVE-2023-6746 is an information disclosure vulnerability in GitHub Enterprise Server where sensitive data is logged, potentially enabling man-in-the-middle attacks when combined with phishing. It affects all versions since 3.7, requiring access to log files, backups, or log streams for exploitation.
💻 Affected Systems
- GitHub Enterprise Server
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
An attacker with access to logs could steal sensitive credentials or tokens, leading to unauthorized access, data breaches, or further compromise of the GitHub Enterprise Server and connected systems.
Likely Case
Limited information exposure if logs are properly secured, but could facilitate targeted attacks if logs are leaked or accessed by insiders.
If Mitigated
Minimal impact with strict access controls, encryption, and monitoring of log files, reducing the risk of unauthorized log access.
🎯 Exploit Status
Exploitation is not straightforward; it depends on log access and social engineering, making it less likely for widespread automated attacks.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 3.7.19, 3.8.12, 3.9.7, 3.10.4, or 3.11.1
Vendor Advisory: https://docs.github.com/en/enterprise-server/admin/release-notes
Restart Required: Yes
Instructions:
1. Backup your GitHub Enterprise Server instance. 2. Download the patched version from GitHub's release page. 3. Follow the upgrade instructions in the GitHub Enterprise Server documentation. 4. Restart the server to apply the patch.
🔧 Temporary Workarounds
Restrict Log Access
linuxLimit access to log files, backups, and log streams to authorized personnel only.
chmod 600 /path/to/logs/*
setfacl -m u:admin:rw /path/to/logs
Encrypt Logs and Backups
allUse encryption for log storage and backup archives to protect sensitive information.
gpg --encrypt --recipient admin@example.com backup.tar.gz
🧯 If You Can't Patch
- Implement strict access controls and monitoring for log files and backup archives.
- Use network segmentation to isolate log storage and limit exposure to potential attackers.
🔍 How to Verify
Check if Vulnerable:
Check the GitHub Enterprise Server version; if it is earlier than the patched versions listed, it is vulnerable.Check Version:
ghe-versionVerify Fix Applied:
After patching, confirm the version matches one of the fixed releases and test logging to ensure no sensitive data is exposed.📡 Detection & Monitoring
Log Indicators:
- Unusual access patterns to log files, such as unauthorized reads or copies of logs containing sensitive data.
Network Indicators:
- Suspicious outbound transfers of log files or backup archives from the server.
SIEM Query:
source="github-enterprise" AND (event="log_access" OR event="backup_download") AND user NOT IN ["authorized_users"]🔗 References
- https://docs.github.com/en/enterprise-server@3.10/admin/release-notes#3.10.4
- https://docs.github.com/en/enterprise-server@3.11/admin/release-notes#3.11.1
- https://docs.github.com/en/enterprise-server@3.7/admin/release-notes#3.7.19
- https://docs.github.com/en/enterprise-server@3.8/admin/release-notes#3.8.12
- https://docs.github.com/en/enterprise-server@3.9/admin/release-notes#3.9.7
- https://docs.github.com/en/enterprise-server@3.10/admin/release-notes#3.10.4
- https://docs.github.com/en/enterprise-server@3.11/admin/release-notes#3.11.1
- https://docs.github.com/en/enterprise-server@3.7/admin/release-notes#3.7.19
- https://docs.github.com/en/enterprise-server@3.8/admin/release-notes#3.8.12
- https://docs.github.com/en/enterprise-server@3.9/admin/release-notes#3.9.7
