User Enumeration Affecting openssl package, versions [0,1.0.2r)


Severity

Recommended
0.0
medium
0
10

CVSS assessment made by Snyk's Security Team. Learn more

Threat Intelligence

EPSS
1.4% (87th percentile)

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications
  • Snyk IDSNYK-UNMANAGED-OPENSSL-2318651
  • published14 Dec 2021
  • disclosed27 Feb 2019
  • creditUnknown

Introduced: 27 Feb 2019

CVE-2019-1559  (opens in a new tab)
CWE-203  (opens in a new tab)

How to fix?

Upgrade openssl to version 1.0.2r or higher.

Overview

Affected versions of this package are vulnerable to User Enumeration. If an application encounters a fatal protocol error and then calls SSL_shutdown() twice (once to send a close_notify, and once to receive one) then OpenSSL can respond differently to the calling application if a 0 byte record is received with invalid padding compared to if a 0 byte record is received with an invalid MAC. If the application then behaves differently based on that in a way that is detectable to the remote peer, then this amounts to a padding oracle that could be used to decrypt data. In order for this to be exploitable "non-stitched" ciphersuites must be in use. Stitched ciphersuites are optimised implementations of certain commonly used ciphersuites. Also the application must call SSL_shutdown() twice even if a protocol error has occurred (applications should not do this but some do anyway). Fixed in OpenSSL 1.0.2r (Affected 1.0.2-1.0.2q).

CVSS Scores

version 3.1