Actively exploited · Published Jul 9, 2021 · Assigned by mitre
CVE-2021-301202FA bypass in Kaseya VSA <= v9.5.6
Critical 9.9
In plain English
A critical-severity security flaw in the affected software. CISA's analysis reports active exploitation. The chance it is exploited in the next 30 days is estimated at 5.7% (higher than 93% of all known vulnerabilities).
Official description
Kaseya VSA before 9.5.7 allows attackers to bypass the 2FA requirement. The need to use 2FA for authentication in enforce client-side instead of server-side and can be bypassed using a local proxy. Thus rendering 2FA useless. Detailed description --- During the login process, after the user authenticates with username and password, the server sends a response to the client with the booleans MFARequired and MFAEnroled. If the attacker has obtained a password of a user and used an intercepting proxy (e.g. Burp Suite) to change the value of MFARequered from True to False, there is no prompt for the second factor, but the user is still logged in.
Affected products (as reported)
References
- https://csirt.divd.nl/2021/07/07/Kaseya-Limited-Disclosure/ x_refsource_CONFIRM
- https://csrit.divd.nl/DIVD-2021-00011 x_refsource_CONFIRM
- https://csrit.divd.nl/CVE-2021-30120 x_refsource_CONFIRM