Cisco IOS XR Software Image Verification Bypass Vulnerability

TL;DR 📌

A medium severity vulnerability has been identified in Cisco IOS XR Software that allows an authenticated local attacker to bypass image signature verification, potentially leading to the installation of unsigned software. No workarounds are available, and users are advised to update to fixed software versions.

What happened 🕵️‍♂️

A vulnerability in the installation process of Cisco IOS XR Software could allow an authenticated, local attacker with root-system privileges to bypass the software image signature verification. This flaw arises from incomplete validation of files during the installation of an .iso file. An attacker could exploit this by modifying the .iso image and installing it on the device, leading to the activation of unsigned software.

Affected products 🖥️

The following Cisco products are affected if they are running a vulnerable release of Cisco IOS XR Software:

• ASR 9000 Series Aggregation Services Routers (64-bit)
• IOS XR White box (IOSXRWBD)
• IOS XRv 9000 Routers
• Network Convergence System (NCS) 540 Series Routers (running an NCS 540-iosxr base image)
• NCS 560 Series Routers
• NCS 1000 Series (NCS 1001, NCS 1002, and NCS 1004)
• NCS 5000 Series Routers
• NCS 5500 Series Routers
• NCS 5700 Series Line Cards and Routers (running an NCS 5500 base image)
• NCS 6000 Series Routers

Fixed software 🔧

Upgrade to the first fixed release in your train (or later):

Workarounds 🧯

There are no workarounds that address this vulnerability.

Risk in context 🎯

The vulnerability has a CVSS score of 6.0, categorized as Medium severity. It requires local access and root privileges to exploit, limiting the exposure to authenticated users. However, the potential for an attacker to load unsigned software poses a significant security risk, especially in sensitive environments.

Fast facts ⚡

• Vulnerability: Cisco IOS XR Software Image Verification Bypass
• CVSS Score: 6.0 (Medium)
• Exploitation: Requires local access and root privileges
• Workarounds: None available
• Fixed Software: Updates available for affected releases

For leadership 🧭

This vulnerability presents a Medium risk to your organization, as it allows authenticated local attackers to bypass software image verification. The exposure is limited to users with root privileges, but the potential for unsigned software installation could lead to significant security breaches.

Remediation Ask: Patch affected devices within 7 days to mitigate risks.

Operational Impact: Expect a brief maintenance window with no configuration drift anticipated.

Now / Next / Later:

• Now: Identify and assess devices running affected versions of Cisco IOS XR Software.
• Next: Schedule and implement the necessary software updates.
• Later: Monitor devices for any unexpected downgrades and validate software integrity regularly.