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CVE-2018-16395: When two OpenSSL::X509::Name objects are compared using ==, depending on the ordering, non-equal objects may…

CVE-2018-16395 is rated critical with a CVSS v3.0 base score of 9.8 and affects Ruby Lang Openssl, along with 3 other products in NVD’s configuration data. Per its scoring, it can be exploited over the network, without authentication, without any user interaction. The scored impact on confidentiality, integrity and availability is the highest available.

Vulnerability description

An issue was discovered in the OpenSSL library in Ruby before 2.3.8, 2.4.x before 2.4.5, 2.5.x before 2.5.2, and 2.6.x before 2.6.0-preview3. When two OpenSSL::X509::Name objects are compared using ==, depending on the ordering, non-equal objects may return true. When the first argument is one character longer than the second, or the second argument contains a character that is one less than a character in the same position of the first argument, the result of == will be true. This could be leveraged to create an illegitimate certificate that may be accepted as legitimate and then used in signing or encryption operations.

Severity breakdown

CVSS v3.0 9.8: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

  • Attack vector: Network. Exploitable remotely over the network, with no need for local or physical access.
  • Attack complexity: Low. No special conditions; the attack can be repeated reliably.
  • Privileges required: None. No account or prior access is needed.
  • User interaction: None. No action from any user is needed.
  • Scope: Unchanged. Impact stays within the vulnerable component.
  • Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
  • Integrity impact: High. Total loss of integrity; data or system state can be fully modified.
  • Availability impact: High. Total loss of availability; the component can be shut down.

Affected products

  • Ruby Lang Openssl: before 2.1.2
  • Ruby Lang: from 2.3.0 up to and including 2.3.7; from 2.4.0 up to and including 2.4.4; from 2.5.0 up to and including 2.5.1; 2.6.0 preview1; 2.6.0 preview2
  • Canonical Ubuntu Linux: 14.04; 16.04; 18.04; 18.10
  • Debian Linux: 8.0; 9.0
  • Red Hat Enterprise Linux: 7.4

References