CVE-2019-15981
📋 TL;DR
CVE-2019-15981 allows authenticated attackers with administrative privileges to perform directory traversal attacks through REST/SOAP API endpoints in Cisco DCNM. This could let attackers access sensitive files outside intended directories. The risk is heightened when combined with authentication bypass vulnerabilities described in a simultaneous advisory.
💻 Affected Systems
- Cisco Data Center Network Manager
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Administrative attacker could read sensitive system files, configuration data, or potentially write files to execute arbitrary code, leading to full system compromise.
Likely Case
Privileged attacker reads sensitive configuration files, extracts credentials, or accesses restricted system files to escalate privileges further.
If Mitigated
With proper access controls and network segmentation, impact limited to unauthorized file reads within the DCNM application scope.
🎯 Exploit Status
Exploitation requires administrative credentials on DCNM. Directory traversal attacks are well-understood attack patterns with many existing tools.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 11.3(1) and later
Vendor Advisory: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20200102-dcnm-path-trav
Restart Required: Yes
Instructions:
1. Download DCNM version 11.3(1) or later from Cisco Software Center. 2. Backup current configuration. 3. Install update following Cisco DCNM upgrade guide. 4. Restart DCNM services.
🔧 Temporary Workarounds
Restrict API Access
linuxLimit network access to DCNM REST and SOAP API endpoints to trusted IP addresses only.
iptables -A INPUT -p tcp --dport 443 -s trusted_ip_range -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP
Implement Strong Authentication Controls
allEnforce multi-factor authentication and strong password policies for all DCNM administrative accounts.
🧯 If You Can't Patch
- Isolate DCNM systems on segmented network with strict firewall rules limiting inbound connections
- Implement comprehensive monitoring of DCNM API access and file system access patterns
🔍 How to Verify
Check if Vulnerable:
Check DCNM version via web interface (Admin > About) or command line: cat /opt/cisco/dcnm/version.txtCheck Version:
cat /opt/cisco/dcnm/version.txtVerify Fix Applied:
Confirm version is 11.3(1) or later and verify no directory traversal via API endpoints using security testing tools.📡 Detection & Monitoring
Log Indicators:
- Unusual API requests with '../' sequences in parameters
- Multiple failed authentication attempts followed by successful admin login
- Access to files outside normal DCNM directories
Network Indicators:
- HTTP requests to DCNM API endpoints containing path traversal sequences
- Unusual file download patterns from DCNM
SIEM Query:
source="dcnm_logs" AND ("../" OR "..\" OR "%2e%2e%2f") AND (uri_path="/rest" OR uri_path="/soap")