CVE-2020-3374
📋 TL;DR
This vulnerability in Cisco SD-WAN vManage Software allows authenticated remote attackers to bypass authorization checks via crafted HTTP requests to the web management interface. Attackers can access sensitive information, modify system configurations, or disrupt availability beyond their authorized privileges. Organizations using affected Cisco SD-WAN vManage versions are impacted.
💻 Affected Systems
- Cisco SD-WAN vManage Software
📦 What is this software?
Sd Wan by Cisco
Sd Wan by Cisco
Sd Wan by Cisco
Sd Wan by Cisco
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise allowing unauthorized configuration changes, data exfiltration, or denial of service affecting SD-WAN operations.
Likely Case
Unauthorized access to sensitive network configuration data and potential privilege escalation within the management system.
If Mitigated
Limited impact with proper network segmentation and access controls preventing exploitation attempts.
🎯 Exploit Status
Requires authenticated access but exploitation involves simple crafted HTTP requests. No public exploit code available at advisory publication.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 20.1.1 and later
Vendor Advisory: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-uabvman-SYGzt8Bv
Restart Required: Yes
Instructions:
1. Download Cisco SD-WAN vManage Software version 20.1.1 or later from Cisco Software Center. 2. Backup current configuration. 3. Upgrade vManage software following Cisco SD-WAN upgrade procedures. 4. Verify successful upgrade and functionality.
🔧 Temporary Workarounds
Restrict Management Interface Access
allLimit access to vManage web interface to trusted IP addresses only using network ACLs or firewall rules.
# Example firewall rule to restrict access
# 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 vManage user accounts.
# Configure TACACS+/RADIUS with MFA
# Ensure password complexity requirements are enforced
🧯 If You Can't Patch
- Isolate vManage management interface behind VPN or jump host with strict access controls
- Implement network segmentation to separate management traffic from production traffic
🔍 How to Verify
Check if Vulnerable:
Check vManage software version via CLI: show version | include Software. If version is earlier than 20.1.1, system is vulnerable.Check Version:
show version | include SoftwareVerify Fix Applied:
After upgrade, verify version is 20.1.1 or later using same command and test authorization controls.📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP requests to management interface
- Authorization failures followed by successful privileged operations
- Configuration changes from non-admin users
Network Indicators:
- HTTP requests with crafted parameters to vManage web interface
- Unusual traffic patterns to management port 443
SIEM Query:
source="vmanage" AND (event_type="auth_failure" OR event_type="config_change") AND user_role!="admin"