Quantum Secular Labs / Blog / Advisories

CVE-2016-4694: Apple OS X Server: Improper Access Control

CVE-2016-4694 is rated critical with a CVSS v3.0 base score of 9.1 and affects Apple OS X Server, along with 1 other product in NVD’s configuration data. Per its scoring, it can be exploited over the network, without authentication, without any user interaction.

Vulnerability description

The Apache HTTP Server in Apple OS X before 10.12 and OS X Server before 5.2 follows RFC 3875 section 4.1.18 and therefore does not protect applications from the presence of untrusted CGI client data in the HTTP_PROXY environment variable, which might allow remote attackers to redirect an application's outbound HTTP traffic to an arbitrary proxy server via a crafted Proxy header in an HTTP request, aka an "httpoxy" issue, a related issue to CVE-2016-5387.

Severity breakdown

CVSS v3.0 9.1: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

  • 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: None. No effect on availability.

Underlying weakness

CWE-284: Improper Access Control

The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.

Affected products

  • Apple OS X Server: up to and including 5.1
  • Apple Mac OS X: up to and including 10.11.6

References