CVE-2024-47176
Description
A security issue has been identified in OpenPrinting CUPS.
The function ppdCreatePPDFromIPP2 in the libppd library is responsible for generating a PostScript Printer Description (PPD) file based on attributes retrieved from an Internet Printing Protocol (IPP) response. Essentially, it takes printer information, usually obtained via IPP, and creates a corresponding PPD file that describes the printer's capabilities (such as supported media sizes, resolutions, color modes, etc.).
PPD files are used by printing systems like CUPS (Common Unix Printing System) to communicate with and configure printers. They provide a standardized format that allows different printers to work with the printing system in a consistent way.
A security issue was discovered in OpenPrinting CUPS. The cups-browsed component is responsible for discovering printers on a network and adding them to the system. In order to do so, the service uses two distinct protocols. For the first one, the service binds on all interfaces on UDP port 631 and accepts a custom packet from any untrusted source. This is exploitable from outside the LAN if the computer is exposed on the public internet. The service also listens for DNS-SD / mDNS advertisements trough AVAHI. In both cases, when a printer is discovered by either the UDP packet or mDNS, its IPP or IPPS url is automatically contacted by cups-browsed and a Get-Printer-Attributes request is sent to it which can leak potentially sensitive system information to an attacker via the User-Agent header.
Security Bulletin
Statement
The cups-browsed service is disabled by default on all versions of RHEL.
Mitigation
See the security bulletin for a detailed mitigation procedure.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.5 | N/A | N/A |
| Attack Vector | Network | N/A | N/A |
| Attack Complexity | Low | N/A | N/A |
| Privileges Required | None | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | High | N/A | N/A |
| Integrity Impact | None | N/A | N/A |
| Availability Impact | None | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Understanding the Weakness (CWE)
Access Control,Other
Technical Impact: Gain Privileges or Assume Identity; Varies by Context; Bypass Protection Mechanism
An attacker can access any functionality that is inadvertently accessible to the source.
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