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CVE-2017-8408: D-Link Dcs 1130 Firmware: Command injection

CVE-2017-8408 is rated critical with a CVSS v3.0 base score of 9.8 and NVD lists D-Link Dcs 1130 Firmware as the affected product. 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 on D-Link DCS-1130 devices. The device provides a user with the capability of setting a SMB folder for the video clippings recorded by the device. It seems that the GET parameters passed in this request (to test if SMB credentials and hostname sent to the device work properly) result in being passed as commands to a "system" API in the function and thus result in command injection on the device. If the firmware version is dissected using binwalk tool, we obtain a cramfs-root archive which contains the filesystem set up on the device that contains all the binaries. The binary "cgibox" is the one that has the vulnerable function "sub_7EAFC" that receives the values sent by the GET request. If we open this binary in IDA-pro we will notice that this follows a ARM little endian format. The function sub_7EAFC in IDA pro is identified to be receiving the values sent in the GET request and the value set in GET parameter "user" is extracted in function sub_7E49C which is then passed to the vulnerable system API call.

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

  • D-Link Dcs 1130 Firmware: all versions listed by NVD

References