Quantum Secular Labs / Blog / Advisories

CVE-2018-7750: Paramiko: Improper Authentication

CVE-2018-7750 is rated critical with a CVSS v3.1 base score of 9.8 and affects Paramiko, along with 10 other products in NVD’s configuration data. 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

transport.py in the SSH server implementation of Paramiko before 1.17.6, 1.18.x before 1.18.5, 2.0.x before 2.0.8, 2.1.x before 2.1.5, 2.2.x before 2.2.3, 2.3.x before 2.3.2, and 2.4.x before 2.4.1 does not properly check whether authentication is completed before processing other requests, as demonstrated by channel-open. A customized SSH client can simply skip the authentication step.

Severity breakdown

CVSS v3.1 9.8: CVSS:3.1/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-287: Improper Authentication

When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.

Affected products

  • Paramiko: before 1.17.6; from 1.18.0 before 1.18.5; from 2.0.0 before 2.0.8; from 2.1.0 before 2.1.5; from 2.2.0 before 2.2.3; from 2.3.0 before 2.3.2; 2.4.0
  • Red Hat Ansible Engine: 2.0; 2.4
  • Red Hat Cloudforms: 4.5; 4.6
  • Red Hat Virtualization: 4.1
  • Red Hat Enterprise Linux Desktop: 6.0
  • Red Hat Enterprise Linux Server: 6.0; 7.0
  • Red Hat Enterprise Linux Server Aus: 6.4; 6.5; 6.6
  • Red Hat Enterprise Linux Server Eus: 6.7
  • Red Hat Enterprise Linux Server Tus: 6.6
  • Red Hat Enterprise Linux Workstation: 6.0
  • Debian Linux: 8.0; 9.0

References