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CVE-2017-5397: Mozilla Firefox: Inclusion of Functionality from Untrusted Control Sphere

CVE-2017-5397 is rated critical with a CVSS v3.0 base score of 9.8 and affects Mozilla Firefox. 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

The cache directory on the local file system is set to be world writable. Firefox defaults to extracting libraries from this cache. This allows for the possibility of an installed malicious application or tools with write access to the file system to replace files used by Firefox with their own versions. This vulnerability affects Firefox < 51.0.3.

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.

Underlying weakness

CWE-829: Inclusion of Functionality from Untrusted Control Sphere

The product imports, requires, or includes executable functionality (such as a library) from a source that is outside of the intended control sphere.

Affected products

  • Mozilla Firefox: before 51.0.3

References