PatchSiren cyber security CVE debrief

CVE-2024-27939 Siemens CVE debrief

A critical unauthenticated arbitrary file upload vulnerability in Siemens RUGGEDCOM CROSSBOW enables remote code execution with system privileges. The vulnerability was disclosed on May 14, 2024, with a CVSS 3.1 score of 9.8. Attackers can exploit this weakness without authentication to upload malicious files and achieve full system compromise. Siemens has released version 5.5 to address this vulnerability. Organizations should prioritize patching given the unauthenticated nature of the attack vector and the high impact potential.

Vendor: Siemens
Product: RUGGEDCOM CROSSBOW
CVSS: CRITICAL 9.8
CISA KEV: Not listed in stored evidence
Original CVE published: 2024-05-14
Original CVE updated: 2024-05-14
Advisory published: 2024-05-14
Advisory updated: 2024-05-14

Who should care

Organizations operating Siemens RUGGEDCOM CROSSBOW systems in industrial control system (ICS) environments, critical infrastructure operators, OT security teams, and network administrators responsible for ruggedized communication equipment in utility, transportation, and industrial sectors.

Technical summary

CVE-2024-27939 is a critical vulnerability in Siemens RUGGEDCOM CROSSBOW that permits unauthenticated users to upload arbitrary files. This weakness can be chained to achieve arbitrary code execution with system-level privileges. The vulnerability is remotely exploitable over the network without requiring authentication or user interaction. The attack complexity is low, making this vulnerability particularly dangerous for exposed systems. Siemens has addressed this issue in version 5.5, which should be deployed immediately to prevent exploitation.

Defensive priority

critical

Recommended defensive actions

Apply Siemens RUGGEDCOM CROSSBOW update to version 5.5 or later immediately
Restrict network access to RUGGEDCOM CROSSBOW management interfaces to authorized administrative hosts only
Monitor for unauthorized file upload attempts and unexpected file system changes on affected systems
Implement network segmentation to isolate RUGGEDCOM CROSSBOW systems from untrusted networks
Review system logs for indicators of compromise, particularly around the disclosure date of May 14, 2024

Evidence notes

Vulnerability details sourced from CISA ICS advisory ICSA-24-137-10 and Siemens security advisory SSA-916916. The advisory confirms unauthenticated arbitrary file upload leading to system-level code execution. CVSS vector AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H indicates network exploitable, low attack complexity, no privileges required, no user interaction, with high impact across confidentiality, integrity, and availability.

Official resources

2024-05-14