CVE-2025-5309: BeyondTrust Privileged Remote Access RCE

CVE-2025-5309 Overview

The chat feature within Remote Support (RS) and Privileged Remote Access (PRA) is vulnerable to a Server-Side Template Injection vulnerability which can lead to remote code execution. This vulnerability allows attackers to inject malicious code into server-side templates, potentially executing arbitrary commands on the server.

Critical Impact

This vulnerability, if exploited, could lead to full system compromise resulting in unauthorized access and control.

Affected Products

• BeyondTrust Privileged Remote Access
• BeyondTrust Remote Support

Discovery Timeline

• Not Available - Vulnerability discovered by Not Available
• Not Available - Responsible disclosure to BeyondTrust
• Not Available - CVE CVE-2025-5309 assigned
• Not Available - BeyondTrust releases security patch
• 2025-06-16 - CVE CVE-2025-5309 published to NVD
• 2025-08-21 - Last updated in NVD database

Technical Details for CVE-2025-5309

Vulnerability Analysis

The Server-Side Template Injection (SSTI) occurs when user input is concatenated unsafely into templates. In this CVE, improper input validation in the chat features of the affected systems allows an attacker to inject payloads resulting in unexpected code execution on the server. Given the CVSS score of 8.6, it’s a critical flaw that demands immediate attention.

Root Cause

Unvalidated user input in template engines that are capable of executing arbitrary code within the chat feature's server environment.

Attack Vector

The vulnerability can be exploited remotely over the network, making it easily accessible and exploitable with no special privileges required.

# Example exploitation code (sanitized)
malicious_payload = "{{% import os %}} {{os.system('whoami')}}"
safe_input = "Hello"
dangerous_input = "{}: {}".format(user_input, malicious_payload)

Detection Methods for CVE-2025-5309

Indicators of Compromise

• Unusual process creations
• Unexpected server CPU or memory usage spikes
• New or unknown connections to external IPs

Detection Strategies

Monitoring for template errors or unusual log entries indicating injection attempts. Implement input sanitation logs specifically monitoring template render functions.

Monitoring Recommendations

Focus on application logs for anomalies and utilize network monitoring to detect unexpected communications. Employ advanced SIEM solutions for real-time detection of exploit attempts.

How to Mitigate CVE-2025-5309

Immediate Actions Required

• Implement input validation and sanitation on all user inputs.
• Disable template engine functionality that allows arbitrary code execution.
• Isolate the environment of the affected components.

Patch Information

BeyondTrust released a patch to address this vulnerability. Ensure systems are updated using the advisory available at BeyondTrust Advisory.

Workarounds

Consider using application-level firewalls to prevent SSTI characters from reaching server endpoints temporarily.

# Configuration example
iptables -A INPUT -p tcp --dport 80 -m string --string "unsafe_payload" --algo bm -j DROP