CVE-2023-6237

Summary

Issue 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.

Affected Software

VendorProductVersion RangeStatus
OpenSSLOpenSSL3.0.0 < 3.0.13affected
OpenSSLOpenSSL3.1.0 < 3.1.5affected
OpenSSLOpenSSL3.2.0 < 3.2.1affected

Weaknesses

  • CWE-606: CWE-606 Unchecked Input for Loop Condition

ADP Enrichment

CVE Program Container

Additional References

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

Additional References

References