title: Timing Oracle in RSA Decryption
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.
problem types: timing based side channel attack
affected:
{
defaultStatus: unaffected
product: OpenSSL
vendor: OpenSSL
versions:
lessThan: 3.0.8, status: affected, version: 3.0.0, versionType: semver
lessThan: 1.1.1t, status: affected, version: 1.1.1, versionType: custom
lessThan: 1.0.2zg, status: affected, version: 1.0.2, versionType: custom
}
metrics:
format: other
other: [
content: {'text': 'MODERATE'}
type: https://www.openssl.org/policies/secpolicy.html
]