CVE-2025-20181
📋 TL;DR
This vulnerability allows authenticated local attackers with privilege level 15 or unauthenticated attackers with physical access to execute persistent code during device boot by bypassing signature verification. It affects Cisco Catalyst 2960X, 2960XR, 2960CX, and 3560CX Series Switches running vulnerable IOS versions. The attacker can break the chain of trust and execute arbitrary code at boot time.
💻 Affected Systems
- Cisco Catalyst 2960X Series Switches
- Cisco Catalyst 2960XR Series Switches
- Cisco Catalyst 2960CX Series Switches
- Cisco Catalyst 3560CX Series Switches
📦 What is this software?
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⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise with persistent boot-level malware that survives reboots, allowing full network access, data exfiltration, and lateral movement within the network.
Likely Case
Local attackers with physical access or compromised admin credentials install persistent backdoors for ongoing network surveillance and control.
If Mitigated
Limited to attackers with physical device access or already-compromised administrative credentials, with network segmentation preventing lateral movement.
🎯 Exploit Status
Unauthenticated exploitation requires physical device access. Authenticated exploitation requires privilege level 15 credentials. Exploit involves placing crafted files in specific locations during boot.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Cisco advisory for specific fixed versions per device model
Vendor Advisory: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-c2960-3560-sboot-ZtqADrHq
Restart Required: Yes
Instructions:
1. Review Cisco advisory for affected device models and versions. 2. Download appropriate fixed IOS software from Cisco. 3. Backup current configuration. 4. Upload new IOS image to device flash. 5. Update boot system command. 6. Reload device to apply new firmware.
🔧 Temporary Workarounds
Physical Security Controls
allRestrict physical access to network equipment through locked cabinets, access controls, and surveillance.
Privilege Access Management
allImplement strict controls for privilege level 15 accounts, including multi-factor authentication and monitoring.
🧯 If You Can't Patch
- Implement strict physical security controls with monitored access to network closets and data centers.
- Segment network to limit impact if device is compromised and monitor for unusual boot-related activity.
🔍 How to Verify
Check if Vulnerable:
Check device model and IOS version against Cisco advisory. Use 'show version' command and compare with affected devices list.Check Version:
show version | include VersionVerify Fix Applied:
After upgrade, verify new IOS version with 'show version' and ensure it matches patched versions in Cisco advisory.📡 Detection & Monitoring
Log Indicators:
- Unexpected device reboots
- Boot process errors or warnings
- Unauthorized configuration changes
- Failed login attempts to privilege level 15 accounts
Network Indicators:
- Unusual network traffic patterns from switch management interfaces
- Unexpected protocols or ports active on switch
SIEM Query:
Search for: (event_type:reboot OR event_type:authentication_failure) AND device_type:catalyst_switch