Quantum Secular Labs / Blog / Advisories

CVE-2017-17877: When the SSH daemon is enabled for local development, the device is publicly available via IPv6 TCP port 22…

CVE-2017-17877 is rated critical with a CVSS v3.0 base score of 9.8 and NVD lists Valvesoftware Steam Link 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 in Valve Steam Link build 643. When the SSH daemon is enabled for local development, the device is publicly available via IPv6 TCP port 22 over the internet (with stateless address autoconfiguration) by default, which makes it easier for remote attackers to obtain access by guessing 24 bits of the MAC address and attempting a root login. This can be exploited in conjunction with CVE-2017-17878.

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

  • Valvesoftware Steam Link Firmware: before 644

References