WWBN/AVideo has CAPTCHA Bypass via Attacker-Controlled Length Parameter and Missing Token Invalidation on Failure

WWBN AVideo is an open source video platform. In versions 29.0 and prior, `objects/getCaptcha.php` accepts the CAPTCHA length (`ql`) directly from the query string with no clamping or sanitization, letting any unauthenticated client force the server to generate a 1-character CAPTCHA word. Combined with a case-insensitive `strcasecmp` comparison over a ~33-character alphabet and the fact that failed validations do NOT consume the stored session token, an attacker can trivially brute-force the CAPTCHA on any endpoint that relies on `Captcha::validation()` (user registration, password recovery, contact form, etc.) in at most ~33 requests per session. Commit bf1c76989e6a9054be4f0eb009d68f0f2464b453 contains a fix.

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

可猜测的验证码

WWBN AVideo 安全漏洞

WWBN AVideo是WWBN团队的一个由PHP编写的视频平台建站系统。 WWBN AVideo 29.0及之前版本存在安全漏洞，该漏洞源于objects/getCaptcha.php直接从查询字符串接受CAPTCHA长度且未进行限制或清理，可能导致任何未经身份验证的客户端强制服务器生成1字符CAPTCHA，结合不区分大小写的strcasecmp比较和验证失败不消耗存储的会话令牌，攻击者可轻易暴力破解任何依赖Captcha::validation的端点上的CAPTCHA。

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