Citrix NetScaler ADC and Gateway Memory Leak Vulnerability

漏洞信息

漏洞名称： Citrix NetScaler ADC and Gateway 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。该漏洞源于处理未初始化的内存时的不当操作，特别是在解析格式错误的POST数据时，特别是login参数。当login字段被包含但没有等号或值时，未初始化的堆栈内存的一部分会以XML响应中的标签形式返回。每次HTTP请求可能会泄露大约127字节的RAM内容。通过重复这些请求，攻击者可以从内存中收集敏感数据，可能包括会话令牌（允许会话劫持和绕过MFA）、认证数据、先前HTTP请求的部分、明文凭证以及其他敏感信息。此漏洞的主要影响包括会话劫持、绕过认证以及数据泄露。为了保护系统，建议立即更新到最新的安全固件，并监控异常的POST请求模式。

产品厂商： Citrix

产品名称： Citrix NetScaler ADC and Gateway

来源： https://github.com/win3zz/CVE-2025-5777

类型： CVE-2025:github search

仓库文件

• DISCLAIMER.md
• README.md
• exploit.py

来源概述

CVE-2025-5777 Citrix NetScaler Memory Leak Exploit

[!WARNING]
This script is intended for educational and research purposes only. Do not use it against systems without explicit permission. Unauthorized access or testing is illegal and unethical.

Overview

This project demonstrates a memory leak vulnerability (CVE-2025-5777) found in Citrix NetScaler appliances. The vulnerability results from improper handling of uninitialized memory when parsing malformed POST data, particularly the login parameter. It’s widely known as CitrixBleed 2 because of its strong resemblance to the infamous CVE-2023-4966 (original CitrixBleed) which was heavily exploited in 2023

When the login field is included without an equal sign or value, a portion of uninitialized stack memory is returned inside the <InitialValue> tag in the XML response.

Data Leaked: Each HTTP request can leak approximately 127 bytes of RAM content. By repeating these requests, attackers can collect sensitive data from memory, which may include:

• Session tokens (allowing session hijacking and bypassing MFA).
• Authentication data.
• Portions of previous HTTP requests.
• Plaintext credentials.
• Other sensitive information.

Script Usage

Requirements / Dependencies

pip3 install aiohttp colorama

Run the script

python3 exploit.py <URL> [options]

Examples

Basic usage:

Verbose with proxy:

How it work

This Python script:

• Send repeated malformed POST requests.
• Parse XML responses.
• Extract leaked memory from <InitialValue> fields.
• Display it in a hex-dump format like the xxd tool.
• Support optional proxying, threading and verbose output for analysis.

Impact

• Session Hijacking: The primary concern is the theft of session tokens, which allows attackers to hijack active user sessions and gain unauthorized access to critical systems, even if multi-factor authentication (MFA) is enabled.
• Bypassing Authentication: Stolen session tokens or credentials can be used to completely bypass the authentication process.
• Data Disclosure: Sensitive information residing in memory can be exposed.

Defense & Mitigation

• Update to the latest secure firmware immediately.
• Monitor for abnormal POST request patterns.

Reference:

• watchTowr Blog Post - Original analysis