CVE-2021-40856 in COMfortel 1400 IP
Summary
by MITRE • 12/13/2021
Auerswald COMfortel 1400 IP and 2600 IP before 2.8G devices allow Authentication Bypass via the /about/../ substring.
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Analysis
by VulDB Data Team • 12/15/2021
The Auerswald COMfortel 1400 IP and 2600 IP devices represent a class of VoIP communication systems widely deployed in enterprise and industrial environments for voice communication services. These devices operate with web-based administrative interfaces that typically require proper authentication to access sensitive configuration parameters and system controls. The vulnerability in question stems from a path traversal flaw that allows unauthorized access to protected administrative resources through a carefully crafted URL sequence involving the /about/../ substring pattern.
This authentication bypass vulnerability specifically exploits improper input validation within the web server component of these devices. When a user submits a request containing the /about/../ path traversal sequence, the device fails to properly sanitize the input and instead processes the request as if it were accessing a legitimate administrative endpoint. The vulnerability manifests in the device's handling of relative paths where the ../ component is not properly stripped or validated, allowing attackers to navigate to restricted directories and access administrative functions without proper credentials.
The operational impact of this vulnerability extends beyond simple unauthorized access to encompass potential system compromise and data exfiltration. An attacker could leverage this bypass to modify critical system configurations, access sensitive communication parameters, or even install malicious firmware updates. The vulnerability affects devices running firmware versions prior to 2.8G, representing a significant security gap in the device lifecycle management where older versions remain in production environments without proper patching. This type of vulnerability aligns with CWE-22 Path Traversal and is categorized under the MITRE ATT&CK framework as privilege escalation through path traversal techniques.
The exploitation of this vulnerability requires minimal technical skill and can be accomplished through standard web browser manipulation or automated tools. Attackers can construct malicious URLs that bypass authentication mechanisms entirely, gaining access to administrative interfaces that should only be accessible to authorized personnel. This creates a significant risk for organizations that rely on these devices for critical communications infrastructure, as the vulnerability could lead to complete system compromise, unauthorized surveillance, or disruption of voice services. Organizations should implement immediate mitigations including firmware updates to version 2.8G or later, network segmentation to isolate these devices, and monitoring for suspicious access patterns to prevent exploitation of this authentication bypass vulnerability.