CVE-2025-23121: Veeam Backup & Replication RCE Vulnerability

CVE-2025-23121 Overview

A vulnerability allowing remote code execution (RCE) on the Backup Server by an authenticated domain user. An attacker can exploit this flaw to execute arbitrary code within the context of the affected service.

Critical Impact
This vulnerability could allow an attacker to execute remote code, potentially compromising the entire system.

Affected Products

Veeam Veeam Backup & Replication

Discovery Timeline

2025-06-19 - CVE CVE-2025-23121 published to NVD
2025-07-15 - Last updated in NVD database

Technical Details for CVE-2025-23121

Vulnerability Analysis

The vulnerability manifests due to improper input validation, allowing an attacker to inject malicious code. The vulnerability is identified as CWE-94: Improper Control of Generation of Code ('Code Injection') and allows remote attackers with minimal privileges to exploit this issue over the network.

Root Cause

The root cause is inadequate sanitization of user-supplied input into the backup server application, enabling crafted input to be executed as code.

Attack Vector

Network-based attacks exploiting this flaw require an authenticated domain user to interact with the vulnerable service.

python

# Example exploitation code (sanitized)
import requests

url = "http://vulnerable-backupserver/"
payload = { 'command': 'malicious_code()' }

response = requests.post(url, data=payload)
print(response.text)

Detection Methods for CVE-2025-23121

Indicators of Compromise

Unexpected outbound network traffic
Unvalidated input data in logs
Unusual application behavior

Detection Strategies

Leverage network traffic analysis tools to identify anomalous patterns indicating attempted exploitation. Use endpoint detection and response (EDR) to monitor signal anomalies as part of behavioral threat detection.

Monitoring Recommendations

Enable verbose logging on the backup server to detect suspicious commands being executed and configure alerts for unauthorized access attempts.

How to Mitigate CVE-2025-23121

Immediate Actions Required

Apply the security patch provided by Veeam.
Restrict network access to the backup server to trusted IP addresses.
Enhance input validation within the application to prevent code injection.

Patch Information

Patches are available at Veeam Advisory.

Workarounds

Network filtering can be configured to block suspicious activity and isolate the affected system if exploitation is suspected.

bash

# Configuration example
iptables -A INPUT -p tcp --dport 80 -s TRUSTED_IP -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP