CVE-2023-3519: Citrix Netscaler ADC RCE Vulnerability

CVE-2023-3519 Overview

CVE-2023-3519 is a critical vulnerability that allows unauthenticated remote code execution on affected systems. This flaw impacts Citrix products, specifically the Netscaler Application Delivery Controller and Netscaler Gateway, enabling attackers to execute arbitrary code over the network without authentication.

Critical Impact
Unauthenticated attackers can execute arbitrary code, leading to full system compromise.

Affected Products

Citrix Netscaler Application Delivery Controller
Citrix Netscaler Gateway

Discovery Timeline

Not Available - Vulnerability discovered by Not Available
Not Available - Responsible disclosure to Citrix
Not Available - CVE CVE-2023-3519 assigned
Not Available - Citrix releases security patch
2023-07-19T18:15:11.513 - CVE CVE-2023-3519 published to NVD
2025-10-24T13:42:51.183 - Last updated in NVD database

Technical Details for CVE-2023-3519

Vulnerability Analysis

This vulnerability is rooted in the improper handling of user inputs. Attackers can exploit this weakness to execute arbitrary commands or code in the context of the affected Citrix systems. The vulnerability, identified as CWE-94, occurs within components of the Netscaler ADC and Gateway, which fail to sanitize input properly, allowing for Remote Code Execution (RCE).

Root Cause

The primary cause is a lack of proper input validation in certain network requests, which are not adequately sanitized, leading to command injection opportunities.

Attack Vector

The attack vector for this vulnerability is via the network, requiring no authentication. This makes it highly exploitable across the internet.

python

# Example exploitation code (sanitized)
import requests

url = "http://target-vulnerable-system"
command = "echo 'Exploiting CVE-2023-3519' > /tmp/exploit"

requests.get(f"{url}/vulnerable-endpoint?cmd={command}")

Detection Methods for CVE-2023-3519

Indicators of Compromise

Unauthorized code execution logs
Unusual network traffic patterns
Unexplained resource consumption

Detection Strategies

Implement monitoring solutions to detect abnormal process executions and network traffic that could indicate exploitation attempts. Use network intrusion detection systems (NIDS) to detect associated attack patterns.

Monitoring Recommendations

Monitor logs for unexpected system command execution
Set alerts for changes in file integrity on critical systems
Deploy comprehensive endpoint protection using SentinelOne to automate threat detection and response

How to Mitigate CVE-2023-3519

Immediate Actions Required

Apply patches released by Citrix immediately
Restrict external access to known affected systems
Enhance firewall rules to detect and block suspicious traffic

Patch Information

Citrix has released a patch to address this flaw. Refer to their security advisory for detailed patching instructions.

Workarounds

As a temporary measure, limit access to the vulnerable systems by using a VPN and allowlist specific IPs only.

bash

# Configuration example to block untrusted networks
iptables -A INPUT -s 0.0.0.0/0 -p tcp --dport 443 -j DROP
iptables -A INPUT -s <trusted-ip> -p tcp --dport 443 -j ACCEPT