CVE-2020-13924
📋 TL;DR
This directory traversal vulnerability in Apache Ambari allows malicious users to construct file names that escape intended directories, enabling unauthorized file downloads. It affects Apache Ambari versions 2.6.2.2 and earlier, potentially exposing sensitive configuration files and credentials.
💻 Affected Systems
- Apache Ambari
📦 What is this software?
Ambari by Apache
⚠️ Risk & Real-World Impact
Worst Case
Attackers download sensitive files like configuration files, credentials, or private keys, leading to complete system compromise and data exfiltration.
Likely Case
Unauthorized access to configuration files containing service credentials, potentially enabling lateral movement within the Ambari-managed cluster.
If Mitigated
Limited impact if proper network segmentation and access controls prevent unauthorized users from reaching Ambari interfaces.
🎯 Exploit Status
Exploitation requires authenticated access to Ambari, but the directory traversal technique is well-known and simple to implement.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Apache Ambari 2.6.2.3 and later
Vendor Advisory: https://mail-archives.apache.org/mod_mbox/ambari-user/202102.mbox/%3CCAEJYuxEQZ_aPwJdAaSxPu-Dva%3Dhc7zZUx3-pzBORbd23g%2BGH1A%40mail.gmail.com%3E
Restart Required: Yes
Instructions:
1. Backup Ambari configuration and databases. 2. Upgrade to Ambari 2.6.2.3 or later following official upgrade procedures. 3. Restart Ambari services to apply the fix.
🔧 Temporary Workarounds
Network Access Restriction
linuxRestrict network access to Ambari web interface to trusted IP addresses only.
iptables -A INPUT -p tcp --dport 8080 -s TRUSTED_IP -j ACCEPT
iptables -A INPUT -p tcp --dport 8080 -j DROP
🧯 If You Can't Patch
- Implement strict network segmentation to isolate Ambari servers from untrusted networks.
- Apply web application firewall (WAF) rules to block directory traversal patterns in HTTP requests.
🔍 How to Verify
Check if Vulnerable:
Check Ambari version via 'ambari-server --version' or web interface. If version is 2.6.2.2 or earlier, system is vulnerable.Check Version:
ambari-server --versionVerify Fix Applied:
After patching, verify version is 2.6.2.3 or later and test that directory traversal attempts are blocked.📡 Detection & Monitoring
Log Indicators:
- HTTP requests containing '../' or similar directory traversal patterns in Ambari access logs
- Unusual file access patterns from Ambari web interface
Network Indicators:
- HTTP requests with encoded directory traversal sequences (e.g., %2e%2e%2f)
SIEM Query:
source="ambari_access.log" AND (url="*../*" OR url="*..%2f*")