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PatchSiren cyber security CVE debrief

CVE-2024-38599 Siemens CVE debrief

A vulnerability in the JFFS2 (Journalling Flash File System 2) implementation within the Linux kernel affects the Siemens SIMATIC S7-1500 TM MFP industrial controller's GNU/Linux subsystem. The flaw stems from improper validation of extended attribute (xattr) node sizes during filesystem operations on flash storage. JFFS2 xattr nodes, unlike regular inode nodes, are not fragmented across multiple eraseblocks and must fit entirely within a single eraseblock. When an oversized xattr value is written, the node can overflow its allocated eraseblock, spilling into adjacent storage regions and corrupting existing filesystem nodes. This results in localized denial-of-service conditions through filesystem corruption rather than remote code execution or information disclosure. The vulnerability requires local access with low privileges and has no user interaction requirements, making it exploitable by authenticated users with shell access to the device's GNU/Linux subsystem. The attack surface is constrained to systems where attackers can execute arbitrary code or manipulate extended attributes on JFFS2-mounted volumes. Siemens has not released a patch as of the advisory's last update, leaving affected deployments reliant on access control mitigations. The vulnerability was disclosed in April 2024 and remains unpatched through subsequent advisory revisions that added related CVEs through September 2025.

Vendor
Siemens
Product
SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
CVSS
MEDIUM 5.5
CISA KEV
Not listed in stored evidence
Original CVE published
2024-04-09
Original CVE updated
2026-05-14
Advisory published
2024-04-09
Advisory updated
2026-05-14

Who should care

Operators of Siemens SIMATIC S7-1500 TM MFP industrial controllers utilizing the GNU/Linux subsystem; industrial cybersecurity teams managing embedded Linux deployments with JFFS2 filesystems; asset owners in manufacturing, process control, and critical infrastructure sectors relying on affected devices for automation and control functions.

Technical summary

The vulnerability exists in JFFS2's handling of extended attribute nodes on flash storage devices. The filesystem implementation fails to validate that requested xattr node sizes do not exceed eraseblock capacity minus cleanmarker overhead. Unlike standard inode nodes which are split and distributed across eraseblocks, xattr nodes must reside contiguously within a single eraseblock. When oversized xattr values are written, the resulting node overflows its eraseblock boundary, overwriting subsequent nodes and causing filesystem corruption. The flaw is triggered through standard extended attribute system calls (setxattr) with large values on JFFS2 volumes. Impact is limited to availability degradation through filesystem corruption; no confidentiality or integrity violations of existing data occur beyond the corruption itself. Attack requires local shell access to the GNU/Linux subsystem with privileges sufficient to write extended attributes.

Defensive priority

medium

Recommended defensive actions

  • Restrict interactive shell access to the GNU/Linux subsystem to trusted personnel only
  • Implement application whitelisting to ensure only trusted binaries execute on affected devices
  • Monitor for unexpected filesystem errors or JFFS2 corruption indicators on deployed systems
  • Review and enforce physical and logical access controls for industrial control system environments
  • Subscribe to Siemens ProductCERT security advisories for patch availability notifications
  • Apply defense-in-depth strategies including network segmentation for affected control systems

Evidence notes

Vulnerability description and affected product identification derived from CISA CSAF advisory ICSA-24-102-01, which references Siemens security advisory SSA-265688. CVSS vector AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H confirms local attack vector with availability impact only. Remediation status of 'none_available' with mitigation guidance documented in source. Timeline of advisory updates through 2025-09-09 indicates ongoing monitoring without patch availability.

Official resources

2024-04-09