CVE-2023-6935

Marvin Attack vulnerability in SP Math All RSA

Description

wolfSSL SP Math All RSA implementation is vulnerable to the Marvin Attack, new variation of a timing Bleichenbacher style attack, when built with the following options to configure: --enable-all CFLAGS="-DWOLFSSL_STATIC_RSA" The define “WOLFSSL_STATIC_RSA” enables static RSA cipher suites, which is not recommended, and has been disabled by default since wolfSSL 3.6.6.  Therefore the default build since 3.6.6, even with "--enable-all", is not vulnerable to the Marvin Attack. The vulnerability is specific to static RSA cipher suites, and expected to be padding-independent. The vulnerability allows an attacker to decrypt ciphertexts and forge signatures after probing with a large number of test observations. However the server’s private key is not exposed.

Remediation

Solution:

  • Upgrade wolfSSL to 5.6.6

Workaround:

  • * Do not enable static RSA cipher suites * Use TLS 1.3 * Build with --enable-sp, or --enable-sp-asm

Category

5.9
CVSS
Severity: Medium
CVSS 3.1 •
EPSS 0.15%
Vendor Advisory wolfssl.com
Affected: wolfSSL wolfSSL
Published at:
Updated at:

References

Link Tags
https://people.redhat.com/~hkario/marvin/ third party advisory technical description
https://www.wolfssl.com/docs/security-vulnerabilities/ vendor advisory

Frequently Asked Questions

What is the severity of CVE-2023-6935?
CVE-2023-6935 has been scored as a medium severity vulnerability.
How to fix CVE-2023-6935?
To fix CVE-2023-6935: Upgrade wolfSSL to 5.6.6
Is CVE-2023-6935 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2023-6935 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2023-6935?
CVE-2023-6935 affects wolfSSL wolfSSL.
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