CVE-2023-6935 Marvin Attack vulnerability in SP Math All RSA
Attackers can decrypt ciphertexts and forge signatures via timing attacks if static RSA is enabled, requiring configuration changes to mitigate.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-6935?
CVE-2023-6935 is a medium-severity vulnerability in Wolfssl Wolfssl, published on 9 Feb 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-203
Which versions are affected by CVE-2023-6935?
It affects 1 product.
Products include Wolfssl Wolfssl.
How do I fix CVE-2023-6935?
Change a configuration setting.
Is CVE-2023-6935 being exploited?
There is no known exploitation of CVE-2023-6935 in the wild and no public exploit code.
Other vulnerabilities in Wolfssl Wolfssl
Sources
Also known as DEBIAN-CVE-2023-6935, GHSA-r36f-f47x-637q, JLSEC-2026-677, UBUNTU-CVE-2023-6935.