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CVE-2023-27350: PaperCut MF/NG Improper Access Control Vulnerability

CVE-2023-27350 is rated critical with a CVSS v3.1 base score of 9.8 and affects PaperCut MF/NG. 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. CISA added it to its Known Exploited Vulnerabilities catalog on 2023-04-21, which means exploitation in the wild has been observed.

Vulnerability description

This vulnerability allows remote attackers to bypass authentication on affected installations of PaperCut NG 22.0.5 (Build 63914). Authentication is not required to exploit this vulnerability. The specific flaw exists within the SetupCompleted class. The issue results from improper access control. An attacker can leverage this vulnerability to bypass authentication and execute arbitrary code in the context of SYSTEM. Was ZDI-CAN-18987.

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-284: Improper Access Control

The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.

Affected products

• Papercut Ng: from 8.0 before 20.1.7; from 21.0.0 before 21.2.11; from 22.0.0 before 22.0.9
• Papercut Mf: from 8.0 before 20.1.7; from 21.0.0 before 21.2.11; from 22.0.0 before 22.0.9

References

• https://www.papercut.com/kb/Main/PO-1216-and-PO-1219
• http://packetstormsecurity.com/files/171982/PaperCut-MF-NG-Authentication-Bypass-Remote-Code-Execution.html
• http://packetstormsecurity.com/files/172022/PaperCut-NG-MG-22.0.4-Authentication-Bypass.html
• http://packetstormsecurity.com/files/172512/PaperCut-NG-MG-22.0.4-Remote-Code-Execution.html
• http://packetstormsecurity.com/files/172780/PaperCut-PaperCutNG-Authentication-Bypass.html
• https://news.sophos.com/en-us/2023/04/27/increased-exploitation-of-papercut-drawing-blood-around-the-internet/
• https://www.zerodayinitiative.com/advisories/ZDI-23-233/
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-27350