OpenSSL 3.0/3.1 FIPS DSA Key Length Check DoS via EVP_PKEY_param_check
CVE-2024-4603 Published on May 16, 2024
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.
Vulnerability Analysis
CVE-2024-4603 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a small impact on availability.
Weakness Types
Unchecked Input for Loop Condition
The product does not properly check inputs that are used for loop conditions, potentially leading to a denial of service or other consequences because of excessive looping.
Excessive Iteration
The software performs an iteration or loop without sufficiently limiting the number of times that the loop is executed. If the iteration can be influenced by an attacker, this weakness could allow attackers to consume excessive resources such as CPU or memory. In many cases, a loop does not need to be infinite in order to cause enough resource consumption to adversely affect the software or its host system; it depends on the amount of resources consumed per iteration.
Products Associated with CVE-2024-4603
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Affected Versions
OpenSSL:- Version 3.0.0 and below 3.0.14 is affected.
- Version 3.1.0 and below 3.1.6 is affected.
- Version 3.2.0 and below 3.2.2 is affected.
- Version 3.3.0 and below 3.3.1 is affected.
- Version 3.0.0 and below 3.0.14 is affected.
- Version 3.1.0 and below 3.1.6 is affected.
- Version 3.2.0 and below 3.2.2 is affected.
- Version 3.3.0 and below 3.3.1 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.