MaxKB: Sandbox escape via LD_PRELOAD bypass

MaxKB is an open-source AI assistant for enterprise. In versions 2.7.1 and below, an incomplete sandbox protection mechanism allows an authenticated user with tool execution privileges to escape the LD_PRELOAD-based sandbox. By env command the attacker can clear the environment variables and drop the sandbox.so hook, leading to unrestricted Remote Code Execution (RCE) and network access. MaxKB restricts untrusted Python code execution via the Tool Debug API by injecting sandbox.so through the LD_PRELOAD environment variable. This intercepts sensitive C library functions (like execve, socket, open) to restrict network and file access. However, a patch allowed the /usr/bin/env utility to be executed by the sandboxed user. When an attacker is permitted to create subprocesses, they can execute the env -i python command. The -i flag instructs env to completely clear all environment variables before running the target program. This effectively drops the LD_PRELOAD environment variable. The newly spawned Python process will therefore execute natively without any sandbox hooks, bypassing all network and file system restrictions. This issue has been fixed in version 2.8.0.

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L

保护机制失效

MaxKB 安全漏洞

MaxKB是1Panel-dev开源的一款基于大语言模型和 RAG 的开源知识库问答系统。 MaxKB 2.7.1及之前版本存在安全漏洞，该漏洞源于沙箱保护机制不完整，可能导致具有工具执行权限的经过身份验证的用户逃逸沙箱，进而导致不受限制的远程代码执行和网络访问。

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