CVE-2023-6237

NameCVE-2023-6237
DescriptionIssue summary: Checking excessively long invalid RSA public keys may take a long time. Impact summary: Applications that use the function EVP_PKEY_public_check() to check RSA public keys may experience long delays. Where the key that is being checked has been obtained from an untrusted source this may lead to a Denial of Service. When function EVP_PKEY_public_check() is called on RSA public keys, a computation is done to confirm that the RSA modulus, n, is composite. For valid RSA keys, n is a product of two or more large primes and this computation completes quickly. However, if n is an overly large prime, then this computation would take a long time. An application that calls EVP_PKEY_public_check() and supplies an RSA key obtained from an untrusted source could be vulnerable to a Denial of Service attack. The function EVP_PKEY_public_check() is not called from other OpenSSL functions however it is called from the OpenSSL pkey command line application. For that reason that application is also vulnerable if used with the '-pubin' and '-check' options on untrusted data. The OpenSSL SSL/TLS implementation is not affected by this issue. The OpenSSL 3.0 and 3.1 FIPS providers are affected by this issue.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs1060858

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
openssl (PTS)buster1.1.1n-0+deb10u3fixed
buster (security)1.1.1n-0+deb10u6fixed
bullseye1.1.1w-0+deb11u1fixed
bullseye (security)1.1.1n-0+deb11u5fixed
bookworm, bookworm (security)3.0.11-1~deb12u2vulnerable
sid, trixie3.2.1-3fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
opensslsourcebuster(not affected)
opensslsourcebullseye(not affected)
opensslsource(unstable)3.1.5-11060858

Notes

[bookworm] - openssl <no-dsa> (Minor issue)
[bullseye] - openssl <not-affected> (Only affects 3.x)
[buster] - openssl <not-affected> (Only affects 3.x)
https://www.openssl.org/news/secadv/20240115.txt
https://github.com/openssl/openssl/commit/e09fc1d746a4fd15bb5c3d7bbbab950aadd005db
https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=a830f551557d3d66a84bbb18a5b889c640c36294 (openssl-3.1)
https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=18c02492138d1eb8b6548cb26e7b625fb2414a2a (openssl-3.0)

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