Pierluigi Paganini March 15, 2022

OpenSSL addressed a high-severity denial-of-service (DoS) vulnerability, tracked as CVE-2022-0778, related to certificate parsing.

OpenSSL released updates to address a high-severity denial-of-service (DoS) vulnerability, tracked as CVE-2022-0778, that affects the BN_mod_sqrt() function used when certificate parsing. The flaw was discovered by the popular Google Project Zero researchers Tavis Ormandy.

An attacker can trigger the vulnerability by crafting a malformed certificate with invalid explicit curve parameters.

“The BN_mod_sqrt() function, which computes a modular square root, contains a bug that can cause it to loop forever for non-prime moduli. Internally this function is used when parsing certificates that contain elliptic curve public keys in compressed form or explicit elliptic curve parameters with a base point encoded in compressed form.” reads the advisory for this flaw. “It is possible to trigger the infinite loop by crafting a certificate that has invalid explicit curve parameters.”

The vulnerability impacts OpenSSL versions 1.0.2, 1.1.1 and 3.0, the maintainers of the project addressed the flaw with the release of versions 1.0.2zd (for premium support customers), 1.1.1n and 3.0.2.

The flaw also affects OpenSSL 1.1.0, but it is out of support and no longer receiving updates.

The fix for this flaw was developed by David Benjamin from Google and Tomáš Mráz from OpenSSL.

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Pierluigi Paganini

(SecurityAffairs – hacking, DoS)

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