On this page

Atomicorp WAF Research Note: CVE-2023-27350

PaperCut - Unauthenticated Remote Code Execution

CVE Details

Status: Attack Blocked by Atomicorp
Technical CPE data

This section lists vulnerable CPE matches retained from the NVD configurations. It supplements the readable affected-product information above.

  • cpe:2.3:a:papercut:papercut_mf:*:*:*:*:*:*:*:*
    • Version start (inclusive): 8.0
    • Version end (exclusive): 20.1.7
    • NVD match criteria ID: E225189C-FF05-402B-A8F6-6BCC8D062B8C
  • cpe:2.3:a:papercut:papercut_mf:*:*:*:*:*:*:*:*
    • Version start (inclusive): 21.0.0
    • Version end (exclusive): 21.2.11
    • NVD match criteria ID: 7D231C34-F58C-4CA1-B158-64778AC17991
  • cpe:2.3:a:papercut:papercut_mf:*:*:*:*:*:*:*:*
    • Version start (inclusive): 22.0.0
    • Version end (exclusive): 22.0.9
    • NVD match criteria ID: A326E88D-635E-4AC1-B5CE-455306FC9D55
  • cpe:2.3:a:papercut:papercut_ng:*:*:*:*:*:*:*:*
    • Version start (inclusive): 8.0
    • Version end (exclusive): 20.1.7
    • NVD match criteria ID: 7F5D942B-C055-4221-8FD7-3F0F252931E4
  • cpe:2.3:a:papercut:papercut_ng:*:*:*:*:*:*:*:*
    • Version start (inclusive): 21.0.0
    • Version end (exclusive): 21.2.11
    • NVD match criteria ID: 4DE19845-02F0-4BB9-BECB-49B34FACB55D
  • cpe:2.3:a:papercut:papercut_ng:*:*:*:*:*:*:*:*
    • Version start (inclusive): 22.0.0
    • Version end (exclusive): 22.0.9
    • NVD match criteria ID: C1852E7B-0B3F-4208-A26E-CB117E0C0CD8

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.

  1. Maintain the observed Atomicorp protections. Keep your Atomicorp commercial rules current and confirm that the selected observed rules (390727 , 392648 ) have not been locally disabled. Atomicorp commercial rules are enabled by default. If you use Atomic WAF, review the applicable policy and rule settings.

  2. Apply the vendor’s remediation. WAF protection is defense in depth and does not replace upgrading or following the affected vendor’s guidance.

    • Affected versions: PaperCut NG version 22.0.5 (Build 63914).
    • No specific CNA/vendor solution or workaround is included in the current CVE Record . Review the vendor’s security advisories and supported-release guidance before making changes.
    • CISA KEV required action: Apply updates per vendor instructions.
    • CISA KEV federal remediation due date: 2023-05-12

  3. Validate after changes. Confirm rule updates are current, review WAF events for the affected application, and test application behavior after vendor upgrades, mitigations, or local policy changes.

Research Notes

Atomicorp WAF protections are designed around attack techniques and exploit behaviors, allowing existing protections to apply across multiple vulnerabilities without requiring a unique rule for every CVE.

Public Vulnerability References

MITRE ATT&CK Context

The following mappings are published by the MITRE Center for Threat-Informed Defense and describe exploitation behavior or potential impact; they do not claim that a WAF rule implements the ATT&CK technique.

Test or Research Source

Research Note Context

This research note documents exploit-technique analysis associated with this vulnerability and references Atomicorp WAF protections observed during engineering review, testing, or validation activities.

Atomicorp security controls are generally designed to identify and mitigate attack techniques and exploit behaviors rather than individual CVE identifiers. As a result, protections developed for one vulnerability may also apply to related attack variants and future vulnerabilities using similar techniques.

Learn More

Atomicorp develops commercially supported security technologies for web applications, servers, endpoints, workloads, and legacy enterprise platforms.

Organizations interested in protecting systems against exploit techniques associated with vulnerabilities such as this one can learn more about:

  • Atomic ModSecurity Rules: commercially maintained WAF rules for ModSecurity deployments, including protections for web attacks, bots, scanners, malware, exploitation attempts, and emerging vulnerability classes.
  • Atomic WAF: an enterprise web application firewall with Atomicorp rules, centralized management, reporting, authentication controls, and operational tooling.
  • Atomic ModSecurity Integrator: a special licensing option for MSPs, MSSPs, OEMs, VARs, reverse proxy providers, and other integrators who want to incorporate Atomicorp ModSecurity rule technology into their own products or services.
  • Atomic OSSEC: an enterprise OSSEC-based intrusion detection, compliance, and security monitoring platform.
  • Atomic Protector: workload protection for Linux, web, cloud, data center, and hybrid environments.

For additional information, product evaluations, or technical discussions, visit https://www.atomicorp.com/ or https://modsecurity.io/ .