Verification Code Hijacking in ScratchVerifier

In ScratchVerifier before commit a603769, an attacker can hijack the verification process to log into someone else's account on any site that uses ScratchVerifier for logins. A possible exploitation would follow these steps: 1. User starts login process. 2. Attacker attempts login for user, and is given the same verification code. 3. User comments code as part of their normal login. 4. Before user can, attacker completes the login process now that the code is commented. 5. User gets a failed login and attacker now has control of the account. Since commit a603769 starting a login twice will generate different verification codes, causing both user and attacker login to fail. For clients that rely on a clone of ScratchVerifier not hosted by the developers, their users may attempt to finish the login process as soon as possible after commenting the code. There is no reliable way for the attacker to know before the user can finish the process that the user has commented the code, so this vulnerability only really affects those who comment the code and then take several seconds before finishing the login.

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

认证机制不恰当

ScratchVerifier 授权问题漏洞

ScratchVerifier是ScratchVerifier团队的一个用于为 Scratch 账户提供验证和授权的软件。 ScratchVerifier commit a603769 之前版本存在安全漏洞，攻击者可利用该漏洞可以劫持验证过程，以登录任何使用ScratchVerifier进行登录的站点上的其他人的帐户。

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