Information Exposure Affecting openssl package, versions <1.1.1n-0+deb11u4


0.0
medium

Snyk CVSS

    Attack Complexity High
    Confidentiality High

    Threat Intelligence

    EPSS 0.15% (50th percentile)
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NVD
5.9 medium
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SUSE
5.9 medium
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Red Hat
5.9 medium

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  • Snyk ID SNYK-DEBIAN11-OPENSSL-3314592
  • published 8 Feb 2023
  • disclosed 8 Feb 2023

How to fix?

Upgrade Debian:11 openssl to version 1.1.1n-0+deb11u4 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream openssl package and not the openssl package as distributed by Debian. See How to fix? for Debian:11 relevant fixed versions and status.

A timing based side channel exists in the OpenSSL RSA Decryption implementation which could be sufficient to recover a plaintext across a network in a Bleichenbacher style attack. To achieve a successful decryption an attacker would have to be able to send a very large number of trial messages for decryption. The vulnerability affects all RSA padding modes: PKCS#1 v1.5, RSA-OEAP and RSASVE.

For example, in a TLS connection, RSA is commonly used by a client to send an encrypted pre-master secret to the server. An attacker that had observed a genuine connection between a client and a server could use this flaw to send trial messages to the server and record the time taken to process them. After a sufficiently large number of messages the attacker could recover the pre-master secret used for the original connection and thus be able to decrypt the application data sent over that connection.