Understanding how CVE-2025-7012 Works

What is Cato Client?

The Cato Client is a user-friendly software tool designed to help businesses securely connect employees to company resources, regardless of where they are. At home, in the office, or on the go.

It’s a key part of Cato Networks’ Secure Access Service Edge (SASE) platform, which blends networking and security into a single, cloud-delivered solution. This simplifies IT operations while enhancing security and performance.

Purpose

The Cato Client enables businesses to:

• Ensure Secure Access: The Cato Client acts like a secure gateway for employees, requiring them to log in with verified credentials (like email/password or company single sign-on). It checks that their devices meet company security standards before allowing access to sensitive apps or data. This ensures only authorized users on safe devices can connect, protecting company information from outsiders or risky devices.
• Support a Flexible Workforce: The client works on various devices (laptops, phones, tablets) and connects employees to company resources from any location. Whether at home, a coffee shop, or an airport. It maintains strong security and consistent performance no matter where employees are, so they can work seamlessly without worrying about location-based restrictions or slowdowns.
• Simplify IT Management: The Cato Client is managed through a single, easy-to-use online dashboard. IT teams can set access rules, push updates, and monitor everything from one place, instead of juggling multiple tools. This centralized control reduces the effort needed to keep systems secure and up-to-date, saving time and minimizing disruptions.
• Boost Productivity: The client optimizes connections to company apps and data, ensuring they load quickly and reliably. By prioritizing important applications and reducing delays, it helps employees get their work done faster. If issues arise, IT can spot and fix them proactively using real-time performance tracking, minimizing downtime.
• Reduce Costs and Complexity: Instead of relying on multiple separate tools for networking, security, and access management, the Cato Client combines these functions into one solution. This eliminates the need for businesses to buy, maintain, or train staff on different systems, lowering costs and simplifying IT operations.

What is the vulnerability?

In Cato Client version 5.4 and below, a local privilege escalation (LPE) vulnerability exists due to improper handling of symbolic links when writing sensitive files during user authentication.

Files Written:

• cato_cred.cfg.tk
• cato_cred.cfg
• A log file

These files are written to the user’s home directory, but the client does not check whether these paths are symbolic links (symlinks) which can be redirected elsewhere on the filesystem.

How does the exploit work?

1. Attacker gains access to a system where the vulnerable Cato Client is installed (even as a low-privileged user).
2. They create a symbolic link in their home directory:

ln -s /etc/passwd ~/cato_cred.cfg

1. When they trigger authentication via the Cato Client, the program, running with elevated privileges, blindly follows the symlink and overwrites /etc/passwd.
2. If the attacker can influence the contents written to that file, they might inject a malicious root-level user.
3. Even if root access isn’t achieved, overwriting a critical file like /etc/passwd can cause Denial of Service, locking users out of the system.

Current Challenges

As of yet, it is a non-weaponized CVE, meaning it can’t be abused just yet. The hurdle is controlling the output of cato client.

Remediation Steps

• Upgrade the cato client to version 5.5 or later.