CVE-2024-4603 (CVSS 5.3)

Description

Issue summary: Checking excessively long DSA keys or parameters may be very slow. Impact summary: Applications that use the functions EVP_PKEY_param_check() or EVP_PKEY_public_check() to check a DSA public key or DSA 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 functions EVP_PKEY_param_check() or EVP_PKEY_public_check() perform various checks on DSA parameters. Some of those computations take a long time if the modulus (`p` parameter) is too large. Trying to use a very large modulus is slow and OpenSSL will not allow using public keys with a modulus which is over 10,000 bits in length for signature verification. However the key and parameter check functions do not limit the modulus size when performing the checks. An application that calls EVP_PKEY_param_check() or EVP_PKEY_public_check() and supplies a key or parameters obtained from an untrusted source could be vulnerable to a Denial of Service attack. These functions are not called by OpenSSL itself on untrusted DSA keys so only applications that directly call these functions may be vulnerable. Also vulnerable are the OpenSSL pkey 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 affected by this issue.

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CVSS v3.1 Score

5.3

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Weakness Type (CWE)

CWE-606 CWE-606

CWE-834 CWE-834

References

Other References

https://github.com/openssl/openssl/commit/3559e868e58005d15c6013a0c1fd832e51c73397 https://github.com/openssl/openssl/commit/53ea06486d296b890d565fb971b2764fcd826e7e https://github.com/openssl/openssl/commit/9c39b3858091c152f52513c066ff2c5a47969f0d https://github.com/openssl/openssl/commit/da343d0605c826ef197aceedc67e8e04f065f740 https://www.openssl.org/news/secadv/20240516.txt http://www.openwall.com/lists/oss-security/2024/05/16/2 https://github.com/openssl/openssl/commit/3559e868e58005d15c6013a0c1fd832e51c73397 https://github.com/openssl/openssl/commit/53ea06486d296b890d565fb971b2764fcd826e7e https://github.com/openssl/openssl/commit/9c39b3858091c152f52513c066ff2c5a47969f0d https://github.com/openssl/openssl/commit/da343d0605c826ef197aceedc67e8e04f065f740

Frequently Asked Questions

What is CVE-2024-4603? +

Issue summary: Checking excessively long DSA keys or parameters may be very slow. Impact summary: Applications that use the functions EVP_PKEY_param_check() or EVP_PKEY_public_check() to check a DSA public key or DSA 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 functions EVP_PKEY_param_check() or EVP_PKEY_public_check() perform various checks on DSA parameters. Some of those computations take a long time if the modulus (`p` parameter) is too large. Trying to use a very large modulus is slow and OpenSSL will not allow using public keys with a modulus which is over 10,000 bits in length for signature verification. However the key and parameter check functions do not limit the modulus size when performing the checks. An application that calls EVP_PKEY_param_check() or EVP_PKEY_public_check() and supplies a key or parameters obtained from an untrusted source could be vulnerable to a Denial of Service attack. These functions are not called by OpenSSL itself on untrusted DSA keys so only applications that directly call these functions may be vulnerable. Also vulnerable are the OpenSSL pkey 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 affected by this issue. It has a CVSS v3.1 base score of 5.3 (MEDIUM).

How severe is CVE-2024-4603? +

CVE-2024-4603 has a CVSS v3.1 score of 5.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

How do I check if I'm vulnerable to CVE-2024-4603? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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