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CVE-2018-18555: Vyos: Improper Neutralization of Special Elements used in an OS Command
CVE-2018-18555 is rated critical with a CVSS v3.0 base score of 9.9 and affects Vyos. Per its scoring, it can be exploited over the network, without any user interaction. The scored impact on confidentiality, integrity and availability is the highest available.
Vulnerability description
A sandbox escape issue was discovered in VyOS 1.1.8. It provides a restricted management shell for operator users to administer the device. By issuing various shell special characters with certain commands, an authenticated operator user can break out of the management shell and gain access to the underlying Linux shell. The user can then run arbitrary operating system commands with the privileges afforded by their account.
Severity breakdown
CVSS v3.0 9.9: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/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: Low. A basic user account is enough.
- User interaction: None. No action from any user is needed.
- Scope: Changed. Impact reaches beyond the vulnerable component to other resources.
- 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-78: Improper Neutralization of Special Elements used in an OS Command
The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command before it is sent to a downstream component.
Affected products
- Vyos: 1.1.8