CVE-2026-78551— RansomLook Login Endpoint Allows Timing-Based Username Enumeration and Unthrottled Authentication Attempts

RansomLook Login Endpoint Allows Timing-Based Username Enumeration and Unthrottled Authentication Attempts

RansomLook contains multiple weaknesses in its authentication endpoint that allow an unauthenticated remote attacker to enumerate valid usernames, perform unrestricted password-guessing attacks, and potentially exhaust application worker resources. For local authentication, the login implementation previously checked whether a submitted username existed before invoking the password hash verification function. Requests containing a nonexistent username therefore returned significantly faster than requests for valid accounts, for which the computationally expensive password verification routine was executed. A remote attacker could measure these response-time differences to determine which usernames correspond to valid RansomLook accounts. In addition, the /login endpoint did not restrict the number or frequency of failed authentication attempts. An attacker could consequently perform password brute-force, dictionary, password-spraying, or credential-stuffing attacks against known accounts without server-side throttling. For valid usernames, each authentication attempt also invokes the password key-derivation function, which consumes a significant amount of CPU time. A sufficiently high rate of login attempts could therefore occupy the application's synchronous Gunicorn workers and cause a denial of service affecting the entire application. The issue has been addressed by always performing password verification using a randomly generated dummy password hash when the supplied username does not exist, eliminating the username-dependent timing discrepancy. Failed authentication attempts are additionally rate-limited per client IP address using Valkey/Redis, with five failed attempts within five minutes resulting in a one-hour block. The reverse-proxy configuration was also updated so that the application derives the client address from a trusted X-Forwarded-For value that cannot be overridden by a client-supplied header.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N

过多认证尝试的限制不恰当

RansomLook 授权问题漏洞

RansomLook是RansomLook团队的一款勒索软件监测与分析平台。 RansomLook 2.0.0及之前版本存在安全漏洞，该漏洞源于登录端点对用户名存在性检查和密码验证处理不当，且未限制失败登录尝试次数，可能导致未经身份验证的远程攻击者枚举有效用户名、进行密码猜测攻击并导致拒绝服务。

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