CVE-2020-26236 Verification Code Hijacking in ScratchVerifier
An attacker can hijack the verification process to log into another user's account by racing to complete the login after the victim submits the code.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2020-26236?
CVE-2020-26236 is a high-severity vulnerability in ScratchVerifier, published on 20 Nov 2020. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
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.
Weakness: CWE-287
Which versions are affected by CVE-2020-26236?
It affects 1 product.
Products include Scratchverifier Scratchverifier.
How do I fix CVE-2020-26236?
No fix has been published for CVE-2020-26236 yet. Limit exposure of the affected software until one is available.
Is CVE-2020-26236 being exploited?
There is no known exploitation of CVE-2020-26236 in the wild and no public exploit code.
Sources
Also known as GHSA-99cr-hvf7-85g9.