HistoryEdit

RUSTSEC-2021-0055

NULL pointer deref in signature_algorithms processing

Issued
Package
openssl-src (crates.io)
Type
Vulnerability
Categories
Aliases
Details
https://www.openssl.org/news/secadv/20210325.txt
CVSS Score
5.9 MEDIUM
CVSS Details
Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
CVSS Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Patched
  • >=111.15

Description

An OpenSSL TLS server may crash if sent a maliciously crafted renegotiation ClientHello message from a client. If a TLSv1.2 renegotiation ClientHello omits the signature_algorithms extension (where it was present in the initial ClientHello), but includes a signature_algorithms_cert extension then a NULL pointer dereference will result, leading to a crash and a denial of service attack.

A server is only vulnerable if it has TLSv1.2 and renegotiation enabled (which is the default configuration). OpenSSL TLS clients are not impacted by this issue.