Missing Required Cryptographic Step Affecting openssl package, versions <1:1.0.2k-19.el7


Severity

Recommended
0.0
medium
0
10

Based on Red Hat Enterprise Linux security rating

    Threat Intelligence

    EPSS
    1.31% (87th percentile)

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  • Snyk ID SNYK-RHEL7-OPENSSL-4932108
  • published 26 Jul 2021
  • disclosed 26 Feb 2019

How to fix?

Upgrade RHEL:7 openssl to version 1:1.0.2k-19.el7 or higher.
This issue was patched in RHSA-2019:2304.

NVD Description

Note: Versions mentioned in the description apply only to the upstream openssl package and not the openssl package as distributed by RHEL. See How to fix? for RHEL:7 relevant fixed versions and status.

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).

References

CVSS Scores

version 3.1
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NVD

5.9 medium
  • Attack Vector (AV)
    Network
  • Attack Complexity (AC)
    High
  • Privileges Required (PR)
    None
  • User Interaction (UI)
    None
  • Scope (S)
    Unchanged
  • Confidentiality (C)
    High
  • Integrity (I)
    None
  • Availability (A)
    None
Expand this section

Red Hat

5.9 medium