Medium severity · published May 16, 2024
CVE-2024-4603
Excessive time spent checking DSA keys and parameters
5.3
CVSS
1.1%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
Low
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)1.1% · higher than 66% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
OP
OpenSSL · OpenSSL
3.0.0 before 3.0.14; 3.1.0 before 3.1.6; 3.2.0 before 3.2.2; 3.3.0 before 3.3.1 · source: vendor, CISA
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2024-4603
CVE.org
https://www.cve.org/CVERecord?id=CVE-2024-4603
github.com
https://github.com/openssl/openssl/commit/3559e868e58005d15c6013a0c1fd832e51c73397
github.com
https://github.com/openssl/openssl/commit/53ea06486d296b890d565fb971b2764fcd826e7e
github.com
https://github.com/openssl/openssl/commit/9c39b3858091c152f52513c066ff2c5a47969f0d
github.com
https://github.com/openssl/openssl/commit/da343d0605c826ef197aceedc67e8e04f065f740
www.openssl.org
https://www.openssl.org/news/secadv/20240516.txt
www.openwall.com
http://www.openwall.com/lists/oss-security/2024/05/16/2
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