CVE-2023-6935

Marvin Attack vulnerability in SP Math All RSA

Published Feb 9, 2024 CVSS 3.1 · 5.9 Medium EPSS < 1% KEV · Not listed
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

Vendor Solution

Upgrade wolfSSL to 5.6.6


Vendor Workaround

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

Tracking

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Advisories

Source ID Title
EUVD EUVD EUVD-2023-59133 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.
History
Type Values Removed Values Added
First Time appeared Wolfssl
Wolfssl wolfssl
CPEs cpe:2.3:a:wolfssl:wolfssl:*:*:*:*:*:*:*:*
Vendors & Products Wolfssl
Wolfssl wolfssl
Weaknesses

Sources

Status
PUBLISHED
Assigner
wolfSSL
Published
Updated
Aug 2, 2024, 8:42 AM
Reserved
Dec 18, 2023, 10:00 PM
Status
Modified
Published
Feb 9, 2024, 11:15 PM
Modified
Jun 17, 2026, 6:51 AM