Citrix NetScaler Memory Leak Vulnerability

漏洞信息

漏洞名称： Citrix NetScaler Memory Leak Vulnerability

漏洞编号：

• CVE： CVE-2025-5777

漏洞类型： 信息泄露

漏洞等级： 严重

漏洞描述： Citrix NetScaler ADC和Gateway设备中存在一个严重的内存泄露漏洞，编号为CVE-2025-5777，也被称为CitrixBleed 2。该漏洞源于在解析登录参数中的畸形POST数据时，对未初始化的堆栈内存处理不当。攻击者可以利用此漏洞直接从内存中泄露敏感数据，包括会话令牌（允许会话劫持和MFA绕过）、认证凭证、部分先前的HTTP请求以及其他敏感信息。每次请求大约可以泄露127字节的RAM内容。通过重复发送畸形请求，攻击者可以提取大量敏感数据。

受影响产品：Citrix NetScaler ADC和Gateway是广泛使用的企业级网络设备，用于提供应用交付和安全的远程访问解决方案。这些设备通常部署在企业网络边缘，处理大量的网络流量和用户认证请求。

漏洞解释：此漏洞属于信息泄露类型，技术根源在于处理用户输入时的内存管理不当。具体来说，当设备接收到缺少’=’和值的登录参数的畸形POST请求时，服务器会错误地返回未初始化的内存内容，嵌入在XML响应的标签中。

影响分析：此漏洞的安全风险极高，攻击者无需认证即可远程利用，导致会话劫持、认证绕过和数据泄露。泄露的会话令牌可以用于劫持活跃用户会话，绕过多因素认证（MFA），而泄露的认证凭证或其他敏感信息可能导致进一步的未授权访问和数据泄露。此外，由于漏洞可以被自动化工具利用，攻击者可以大规模地收集敏感信息，对受影响组织造成广泛的安全威胁。

产品厂商： Citrix

产品名称： Citrix NetScaler ADC and Gateway

来源： https://github.com/bughuntar/CVE-2025-5777

类型： CVE-2025:github search

仓库文件

• DISCLAIMER.md
• README.md
• citrix_memory_leak.py

来源概述

CVE-2025-5777 Citrix NetScaler Memory Leak Exploit (CitrixBleed 2)

---

Overview

This repository contains a proof-of-concept (PoC) exploit script for the CVE-2025-5777 vulnerability, also known as CitrixBleed 2, a critical memory leak affecting Citrix NetScaler ADC and Gateway appliances.

The vulnerability arises from improper handling of uninitialized stack memory when parsing malformed POST data on the login parameter. Exploiting this flaw allows an attacker to leak sensitive data directly from memory, including:

• Session tokens (enabling session hijacking and MFA bypass)
• Authentication credentials
• Portions of previous HTTP requests
• Other sensitive information

Each request can leak approximately 127 bytes of RAM content. By repeatedly sending malformed requests, an attacker can extract significant sensitive data.

---

Disclaimer

This project is intended strictly for educational and research purposes only. Unauthorized use against systems without explicit permission is illegal and unethical.

Please read the full DISCLAIMER before usage.

---

Features

• Sends malformed POST requests to trigger memory leak
• Parses XML responses to extract leaked data from <InitialValue> tags
• Displays leaked memory in hex dump format
• Supports concurrency with configurable thread count
• Optional proxy support for request routing
• Verbose/debug mode for detailed output

---

Requirements

• Python 3.8+
• aiohttp library
• colorama library

Install dependencies via:

pip3 install aiohttp colorama
````

---

### Usage

```bash
python3 citrix_memory_leak.py <BASE_URL> [options]

Arguments

• <BASE_URL>: Base URL of the target Citrix NetScaler (e.g., http://target.com)

Options

Flag	Description
-v, --verbose	Enable verbose debug output
-p, --proxy	HTTP proxy URL (e.g., http://127.0.0.1:8080)
-t, --threads	Number of concurrent requests (default: 10)

Examples

Basic scan:

python3 citrix_memory_leak.py http://target.com

Verbose scan with proxy and 20 threads:

python3 citrix_memory_leak.py http://target.com -v -p http://127.0.0.1:8080 -t 20

---

How It Works

1. Sends repeated malformed POST requests to /p/u/doAuthentication.do with the login parameter missing the = and value.
2. The server improperly returns uninitialized memory content embedded inside the <InitialValue> XML tag.
3. The script extracts and displays this leaked memory as a hex dump.
4. By repeating this, attackers can accumulate sensitive data like tokens and credentials.

---

Impact

• Session Hijacking: Leak of session tokens enables takeover of active user sessions, bypassing MFA.
• Authentication Bypass: Stolen credentials or tokens grant unauthorized access.
• Data Disclosure: Sensitive information residing in memory can be exposed.

---

Mitigation

• Update Firmware: Upgrade Citrix NetScaler ADC/Gateway devices to the latest secure firmware immediately.
• Monitoring: Watch for abnormal POST request patterns targeting /p/u/doAuthentication.do.
• Network Controls: Employ strict access controls and web application firewalls.

---

References

• watchTowr Blog Analysis
• CVE-2025-5777 Details

---

Legal Disclaimer

See DISCLAIMER.md for the full legal terms and usage restrictions.

---

Author

Professor the Hunter (GitHub: @bughuntar)

---

This repository is provided for educational and research purposes only. Use responsibly and ethically.

---