CVE-2024-20352: Cisco Emergency Responder Path Traversal

CVE-2024-20352 Overview

CVE-2024-20352 is a directory traversal vulnerability in the web-based management interface of Cisco Emergency Responder. An authenticated, remote attacker can send crafted HTTP requests to the web UI to read, upload, or delete arbitrary files on the affected device. Successful exploitation grants the attacker the ability to perform arbitrary actions with the privilege level of the authenticated user, including access to password files and log files. The flaw is tracked under CWE-22 and CWE-23 for improper limitation of a pathname to a restricted directory.

Critical Impact
Authenticated attackers can traverse the file system of Cisco Emergency Responder to read sensitive files, upload malicious content, and delete files, compromising the confidentiality, integrity, and availability of the emergency call routing system.

Affected Products

Cisco Emergency Responder 14
Cisco Emergency Responder 14SU1, 14SU2, 14SU3
Cisco Emergency Responder 14SU3a

Discovery Timeline

2024-04-03 - CVE-2024-20352 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2024-20352

Vulnerability Analysis

Cisco Emergency Responder provides enhanced 911 (E911) services for Cisco Unified Communications Manager deployments. The vulnerability resides in the web UI of the appliance and stems from insufficient validation of user-supplied path input in HTTP request parameters. An attacker with valid credentials on the device can submit crafted requests containing path traversal sequences to access resources outside the intended web directory.

Because the web interface serves privileged administrative functions, exploitation permits interaction with sensitive resources on the underlying operating system. The Cisco advisory notes that an attacker can read password or log files and both upload and delete existing files. This provides a foothold for persistence, credential theft, and further lateral movement within the unified communications environment.

Root Cause

The root cause is insufficient input sanitization for file path parameters processed by the web UI. Path components such as ../ sequences are not neutralized before being appended to file system operations, allowing the application to resolve paths outside of its intended working directory.

Attack Vector

Exploitation requires network access to the web management interface and valid authentication credentials on the affected device. The attacker submits HTTP requests with traversal sequences embedded in parameters that the application uses to build file paths. The vulnerability does not require user interaction. See the Cisco Security Advisory for the vendor description.

No verified public proof-of-concept code is currently available. Refer to the vendor advisory for authoritative technical details.

Detection Methods for CVE-2024-20352

Indicators of Compromise

HTTP requests to the Cisco Emergency Responder web UI containing directory traversal sequences such as ../, ..%2f, or encoded variants in query strings or POST bodies.
Unexpected file upload, modification, or deletion events in the Emergency Responder application directories.
Access to sensitive files such as password stores or system log files by low-privilege authenticated web sessions.

Detection Strategies

Inspect web server access logs on the Emergency Responder appliance for traversal patterns and abnormal parameter values submitted by authenticated users.
Correlate authentication events with file system changes to identify a single account performing both login and unusual file operations.
Alert on outbound file transfers or exfiltration attempts originating from the Emergency Responder host shortly after authenticated sessions.

Monitoring Recommendations

Forward Emergency Responder web UI logs and audit logs to a central SIEM for retention and correlation.
Baseline normal administrator activity on the web UI, then alert on deviations such as bulk file access or off-hours administrative actions.
Monitor privileged account usage on unified communications infrastructure and enforce alerting on failed and successful logins from unexpected sources.

How to Mitigate CVE-2024-20352

Immediate Actions Required

Apply the fixed software release provided in the Cisco Security Advisory cisco-sa-cem-csrf-suCmNjFr.
Restrict access to the Emergency Responder web management interface to trusted management networks only.
Rotate credentials for any accounts on affected systems, especially administrator accounts, in case of prior compromise.

Patch Information

Cisco has released software updates that remediate CVE-2024-20352. Customers running Cisco Emergency Responder 14, 14SU1, 14SU2, 14SU3, and 14SU3a should upgrade to a fixed release as documented in the vendor advisory. There are no vendor-supplied workarounds that address this vulnerability; software upgrade is required.

Workarounds

No official workarounds are provided by Cisco. Apply the fixed release.
As a compensating control, place the web UI behind a management VLAN or jump host with strict access control lists.
Enforce multi-factor authentication and least privilege for administrative accounts to limit the impact of credential compromise.

bash

# Verify installed Cisco Emergency Responder version via CLI
show version active

# Restrict web UI access at the network boundary (example ACL concept)
access-list MGMT_ACL permit tcp <trusted_mgmt_subnet> host <cer_host> eq 443
access-list MGMT_ACL deny   tcp any host <cer_host> eq 443