CVE-2020-26074
📋 TL;DR
This vulnerability in Cisco SD-WAN vManage software allows authenticated local attackers to gain escalated privileges by exploiting improper path validation in file transfer functions. Attackers can overwrite arbitrary files to modify the system and achieve privilege escalation. Only authenticated local users on affected Cisco vManage systems are impacted.
💻 Affected Systems
- Cisco SD-WAN vManage Software
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with root/administrator access, allowing data theft, service disruption, and persistent backdoor installation.
Likely Case
Privilege escalation from authenticated user to root/admin, enabling unauthorized configuration changes and access to sensitive network management data.
If Mitigated
Limited impact with proper network segmentation and minimal user access, though local authenticated users could still exploit.
🎯 Exploit Status
Exploitation requires authenticated access but is technically straightforward once authentication is achieved. No public exploit code is known.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 20.3.1 and later
Vendor Advisory: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-vmanage-escalation-Jhqs5Skf
Restart Required: Yes
Instructions:
1. Download Cisco SD-WAN vManage version 20.3.1 or later from Cisco Software Center. 2. Backup current configuration. 3. Apply the update following Cisco's SD-WAN upgrade procedures. 4. Reboot the system as required by the update process.
🔧 Temporary Workarounds
No workarounds available
allCisco states there are no workarounds for this vulnerability
🧯 If You Can't Patch
- Restrict local access to vManage systems to only essential, trusted administrators
- Implement strict monitoring and logging of file system changes and privilege escalation attempts
🔍 How to Verify
Check if Vulnerable:
Check vManage software version via CLI: 'show version' or web interface System > Software. If version is below 20.3.1, system is vulnerable.Check Version:
show version | include vManageVerify Fix Applied:
After patching, verify version is 20.3.1 or higher using 'show version' command. Test file transfer functionality to ensure normal operation.📡 Detection & Monitoring
Log Indicators:
- Unusual file overwrite attempts in system logs
- Multiple failed then successful privilege escalation attempts
- Abnormal file transfer operations with crafted paths
Network Indicators:
- Unusual SSH or console access patterns to vManage systems
- Anomalous administrative traffic to vManage interfaces
SIEM Query:
source="vmanage" AND (event_type="file_modification" OR event_type="privilege_escalation") AND status="success"