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CVE-2016-9683: Dell Sonicwall Secure Remote Access Server: Command injection

CVE-2016-9683 is rated critical with a CVSS v3.0 base score of 9.8 and affects Dell Sonicwall Secure Remote Access Server. 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 SonicWall Secure Remote Access server (version 8.1.0.2-14sv) is vulnerable to a Remote Command Injection vulnerability in its web administrative interface. This vulnerability occurs in the 'extensionsettings' CGI (/cgi-bin/extensionsettings) component responsible for handling some of the server's internal configurations. The CGI application doesn't properly escape the information it's passed when processing a particular multi-part form request involving scripts. The filename of the 'scriptname' variable is read in unsanitized before a call to system() is performed - allowing for remote command injection. Exploitation of this vulnerability yields shell access to the remote machine under the nobody user account. This is SonicWall Issue ID 181195.

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-77: Improper Neutralization of Special Elements used in a Command

The product constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component.

Affected products

  • Dell Sonicwall Secure Remote Access Server: 8.1.0.2-14sv

References