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Hermes Codex

CVE-2025-29635: Command injection vulnerability in D-Link DIR-823X router firmware

Executive Summary

Section titled “Executive Summary”

CVE-2025-29635 represents a critical security deficiency identified within the firmware of D-Link DIR-823X routers. This vulnerability is classified as a command injection flaw, specifically residing within the /goform/set_prohibiting endpoint. Technical analysis confirms that firmware versions 240126 and 240802 are susceptible to exploitation. Successful exploitation permits an attacker to execute arbitrary commands on the affected hardware, potentially compromising device integrity and confidentiality. The vulnerability is currently recognized within the CISA Known Exploited Vulnerabilities (KEV) catalog, indicating active exploitation in the wild.

Technical Analysis

Section titled “Technical Analysis”

The identified vulnerability stems from improper validation of input parameters processed by the /goform/set_prohibiting endpoint. A threat actor can transmit a maliciously crafted POST request to this interface, bypassing existing security controls to execute system-level commands. This command injection capability enables unauthorized control over the device, facilitating activities such as the installation of persistent backdoors, data exfiltration, or participation in larger botnet operations. Given the nature of the endpoint, the vulnerability primarily affects the administrative interface of the D-Link device.

Forensic Markers

Section titled “Forensic Markers”

Security monitoring and incident response activities should prioritize detection of the following indicators:

  • Unauthorized POST requests targeting the /goform/set_prohibiting path within web server access logs.
  • Identification of anomalous binary payloads or shell scripts residing within device memory or temporary directories.
  • Unexplained modifications to device configurations or the creation of unauthorized user accounts, which frequently indicate the establishment of persistence following successful exploitation.

Mitigation and Detection

Section titled “Mitigation and Detection”

Immediate application of vendor-supplied patches is strongly advised. In environments where patching is delayed, access to the administrative interface should be strictly restricted to trusted internal networks. Network intrusion detection systems (NIDS) and host-based monitoring should be implemented to identify the aforementioned forensic indicators.

title: Suspicious POST Request to D-Link set_prohibiting Endpoint
status: experimental
description: Detects suspicious POST requests to the vulnerable /goform/set_prohibiting endpoint in D-Link DIR-823X firmware, indicating a command injection attempt.
logsource:
  category: web_server
  product: d-link_router
detection:
  selection:
    uri: '/goform/set_prohibiting'
    method: 'POST'
  condition: selection
level: high