SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2022-4304

To achieve a successful decryption an attacker would have to be able to send a very large number of trial messages for decryption.

MEDIUM 5.9EPSS 16.2%

Does this matter?

EPSS puts the probability of exploitation in the next 30 days at 16.2%, higher than 97% of all known CVEs. Patch or mitigate before the next change window.

Description

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.

CVSS 3.1
5.9 MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
EPSS
16.20% probability · 97th percentile
CISA KEV
Not listed
Weakness
CWE-203
Affected
openssl/openssl · stormshield/endpoint security · stormshield/sslvpn · stormshield/stormshield network security
Source
openssl-security@openssl.org

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.