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CVE-2017-8283: Debian Dpkg: Path traversal

CVE-2017-8283 is rated critical with a CVSS v3.0 base score of 9.8 and affects Debian Dpkg. 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

dpkg-source in dpkg 1.3.0 through 1.18.23 is able to use a non-GNU patch program and does not offer a protection mechanism for blank-indented diff hunks, which allows remote attackers to conduct directory traversal attacks via a crafted Debian source package, as demonstrated by use of dpkg-source on NetBSD.

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-22: Improper Limitation of a Pathname to a Restricted Directory

The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.

Affected products

Debian Dpkg: 1.3.0; 1.3.1; 1.3.2; 1.3.3; 1.3.4; 1.3.5; 1.3.6; 1.3.7; 1.3.8; 1.3.9; 1.3.10; 1.3.11