Issue summary: Checking excessively long DH keys or parameters may be very slow. Impact summary: Applications that use the functions DH_check(), DH_check_ex() or EVP_PKEY_param_check() to check a DH key or DH parameters may experience l…

Overview

Issue summary: Checking excessively long DH keys or parameters may be very slow.

Impact summary: Applications that use the functions DH_check(), DH_check_ex() or EVP_PKEY_param_check() to check a DH key or DH parameters may experience long delays. Where the key or parameters that are being checked have been obtained from an untrusted source this may lead to a Denial of Service.

The function DH_check() performs various checks on DH parameters. After fixing CVE-2023-3446 it was discovered that a large q parameter value can also trigger an overly long computation during some of these checks. A correct q value, if present, cannot be larger than the modulus p parameter, thus it is unnecessary to perform these checks if q is larger than p.

An application that calls DH_check() and supplies a key or parameters obtained from an untrusted source could be vulnerable to a Denial of Service attack.

The function DH_check() is itself called by a number of other OpenSSL functions. An application calling any of those other functions may similarly be affected. The other functions affected by this are DH_check_ex() and EVP_PKEY_param_check().

Also vulnerable are the OpenSSL dhparam and pkeyparam command line applications when using the "-check" option.

The OpenSSL SSL/TLS implementation is not affected by this issue.

The OpenSSL 3.0 and 3.1 FIPS providers are not affected by this issue.

Affected

• openssl >= 3.0.0, < 3.0.10
• openssl >= 3.1.0, < 3.1.2
• openssl = 1.0.2
• openssl = 1.0.2a
• openssl = 1.0.2b
• openssl = 1.0.2c
• openssl = 1.0.2d
• openssl = 1.0.2e
• openssl = 1.0.2f
• openssl = 1.0.2g
• openssl = 1.0.2h
• openssl = 1.0.2i
• openssl = 1.0.2j
• openssl = 1.0.2k
• openssl = 1.0.2l
• openssl = 1.0.2m
• openssl = 1.0.2n
• openssl = 1.0.2o
• openssl = 1.0.2p
• openssl = 1.0.2q
• openssl = 1.0.2r
• openssl = 1.0.2s
• openssl = 1.0.2t
• openssl = 1.0.2u
• openssl = 1.0.2v
• openssl = 1.0.2w
• openssl = 1.0.2x
• openssl = 1.0.2y
• openssl = 1.0.2za
• openssl = 1.0.2zb
• openssl = 1.0.2zc
• openssl = 1.0.2zd
• openssl = 1.0.2ze
• openssl = 1.0.2zf
• openssl = 1.0.2zg
• openssl = 1.0.2zh
• openssl = 1.1.1
• openssl = 1.1.1a
• openssl = 1.1.1b
• openssl = 1.1.1c
• openssl = 1.1.1d
• openssl = 1.1.1e
• openssl = 1.1.1f
• openssl = 1.1.1g
• openssl = 1.1.1h
• openssl = 1.1.1i
• openssl = 1.1.1j
• openssl = 1.1.1k
• openssl = 1.1.1l
• openssl = 1.1.1m
• openssl = 1.1.1n
• openssl = 1.1.1o
• openssl = 1.1.1p
• openssl = 1.1.1q
• openssl = 1.1.1r
• openssl = 1.1.1s
• openssl = 1.1.1t
• openssl = 1.1.1u

Remediation

Upgrade past the affected range:

• openssl 3.1.2