CVE-2025-20161
📋 TL;DR
This vulnerability allows authenticated local administrators on affected Cisco Nexus switches to execute arbitrary commands with root privileges by installing a malicious software image. It affects Cisco Nexus 3000 and 9000 Series Switches running in standalone NX-OS mode. Attackers need valid administrator credentials to exploit this command injection flaw.
💻 Affected Systems
- Cisco Nexus 3000 Series Switches
- Cisco Nexus 9000 Series Switches
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise allowing attacker to execute any command as root, potentially leading to network disruption, data exfiltration, or persistence mechanisms.
Likely Case
Privileged attacker with legitimate credentials installs malicious image to gain persistent backdoor access or execute specific malicious commands.
If Mitigated
With proper image validation and access controls, exploitation requires bypassing multiple security layers, limiting impact to isolated incidents.
🎯 Exploit Status
Exploitation requires physical or remote administrative access to install a crafted software image.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Cisco advisory for specific fixed versions
Vendor Advisory: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-nxos-ici-dpOjbWxk
Restart Required: Yes
Instructions:
1. Download patched software from Cisco.com 2. Validate image hash 3. Install using 'install all' command 4. Reboot device
🔧 Temporary Workarounds
Image Hash Validation
allAlways validate SHA512 hash of software images before installation
show system internal hash sha512 file bootflash:image.bin
Restrict Administrative Access
allLimit administrative access to trusted personnel and implement multi-factor authentication
🧯 If You Can't Patch
- Implement strict access controls for administrative interfaces
- Monitor for unauthorized software installation attempts and validate all image hashes before installation
🔍 How to Verify
Check if Vulnerable:
Check if device is Nexus 3000/9000 series running standalone NX-OS modeCheck Version:
show versionVerify Fix Applied:
Verify installed software version matches patched version from Cisco advisory📡 Detection & Monitoring
Log Indicators:
- Unauthorized software installation attempts
- Unexpected system reboots
- Unusual command execution in logs
Network Indicators:
- Unexpected outbound connections from switch management interface
- Anomalous traffic patterns
SIEM Query:
Search for 'install' commands from non-standard administrative accounts or outside maintenance windows