CVE-2021-1400
📋 TL;DR
This vulnerability in Cisco Small Business Wireless Access Points allows authenticated remote attackers to access sensitive information or execute arbitrary commands on affected devices. Attackers with valid credentials can exploit web management interface flaws to potentially compromise device integrity and confidentiality. Affected devices include Cisco Small Business 100, 300, and 500 Series Wireless Access Points.
💻 Affected Systems
- Cisco Small Business 100 Series Wireless Access Points
- Cisco Small Business 300 Series Wireless Access Points
- Cisco Small Business 500 Series Wireless Access Points
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise allowing attacker to reconfigure network settings, intercept traffic, install persistent backdoors, or use device as pivot point into internal network.
Likely Case
Unauthorized access to sensitive configuration data, credential harvesting, or limited command execution affecting device functionality.
If Mitigated
Limited impact due to network segmentation, strong authentication controls, and restricted management interface access.
🎯 Exploit Status
Exploitation requires valid credentials; complexity is low once authenticated
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Refer to Cisco Security Advisory for specific fixed firmware versions per model
Vendor Advisory: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sb-wap-multi-ZAfKGXhF
Restart Required: Yes
Instructions:
1. Identify affected device model and current firmware version. 2. Download appropriate fixed firmware from Cisco support portal. 3. Backup current configuration. 4. Upload and install new firmware via web interface or CLI. 5. Verify installation and restore configuration if needed.
🔧 Temporary Workarounds
Restrict Management Interface Access
allLimit access to web management interface to trusted IP addresses only
Configure ACLs or firewall rules to restrict access to management IP/ports
Enforce Strong Authentication
allImplement complex passwords and multi-factor authentication if supported
Change default credentials
Enable RADIUS/TACACS+ authentication if available
🧯 If You Can't Patch
- Segment affected devices on isolated network VLANs
- Disable web management interface and use CLI-only management if possible
🔍 How to Verify
Check if Vulnerable:
Check device firmware version against Cisco advisory; review logs for unauthorized access attempts to web interfaceCheck Version:
show version (CLI) or check System Information in web interfaceVerify Fix Applied:
Confirm firmware version matches patched version in Cisco advisory; test management interface functionality📡 Detection & Monitoring
Log Indicators:
- Multiple failed authentication attempts followed by successful login
- Unusual configuration changes
- Commands executed at unusual times
Network Indicators:
- Unexpected outbound connections from access points
- Traffic patterns inconsistent with normal operations
SIEM Query:
source="cisco-wap" AND (event_type="authentication" AND result="success") AND src_ip NOT IN [trusted_management_ips]