CVE-2024-20404: Cisco Finesse SSRF Vulnerability

CVE-2024-20404 Overview

CVE-2024-20404 is a Server-Side Request Forgery (SSRF) vulnerability in the web-based management interface of Cisco Finesse. An unauthenticated, remote attacker can exploit this flaw by sending a crafted HTTP request to an affected device. Successful exploitation allows the attacker to obtain limited sensitive information from services associated with the affected system.

The vulnerability is tracked under CWE-918: Server-Side Request Forgery. Cisco published the corresponding advisory on June 5, 2024, addressing affected releases of Cisco Finesse 11.6(1) and 12.6(2).

Critical Impact

An unauthenticated remote attacker can coerce the Finesse server to issue arbitrary HTTP requests, exposing limited sensitive data from internal services reachable by the appliance.

Affected Products

• Cisco Finesse 11.6(1) base release and engineering specials ES4 through ES8
• Cisco Finesse 12.6(2) base release and engineering specials ES01 and ES02
• Cisco Finesse web-based management interface

Discovery Timeline

• 2024-06-05 - CVE-2024-20404 published to NVD
• 2024-06-05 - Cisco releases security advisory cisco-sa-finesse-ssrf-rfi-Um7wT8Ew
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2024-20404

Vulnerability Analysis

The flaw exists in HTTP request handling within the Cisco Finesse web-based management interface. The interface accepts user-supplied input that influences outbound HTTP requests issued by the server. Because that input is not adequately validated, an attacker can direct the Finesse host to fetch resources from arbitrary destinations.

SSRF flaws of this class allow attackers to pivot through the affected application to reach internal endpoints. In a contact-center deployment such as Finesse, those reachable services may include administrative interfaces, configuration endpoints, or metadata services that are not exposed externally.

The attack requires no authentication, no user interaction, and is exploitable over the network. Confidentiality is impacted to a limited extent. Integrity and availability are not affected based on the vendor description.

Root Cause

The root cause is insufficient validation of user-supplied input within specific HTTP requests processed by the management interface. The application uses attacker-controlled values when constructing outbound requests without enforcing an allowlist of destinations or validating URL components.

Attack Vector

Exploitation requires only network reachability to the Finesse management interface. An attacker sends a crafted HTTP request containing a manipulated parameter that controls a target URL. The Finesse server then performs the request on behalf of the attacker and returns limited content from the targeted internal service.

The vulnerability mechanism is described in prose only. See the Cisco Security Advisory for vendor technical detail. No verified public proof-of-concept code is available at the time of writing.

Detection Methods for CVE-2024-20404

Indicators of Compromise

• Outbound HTTP requests originating from the Finesse server to unexpected internal hosts or cloud metadata endpoints such as 169.254.169.254.
• Anomalous HTTP request patterns to the Finesse management interface containing URL-encoded parameters that reference internal IP ranges or localhost.
• Web server logs showing requests to Finesse endpoints with parameters containing protocol handlers such as file://, http://, or gopher://.

Detection Strategies

• Inspect Finesse access logs for HTTP requests containing suspicious URL-like parameter values directed at the management interface.
• Correlate outbound network connections from the Finesse appliance against an expected destination baseline and alert on deviations.
• Apply web application firewall (WAF) signatures that flag SSRF-style payloads, including private address ranges, link-local addresses, and non-HTTP schemes.

Monitoring Recommendations

• Enable verbose HTTP request logging on the Finesse management interface and forward logs to a centralized SIEM for retention and analysis.
• Monitor egress traffic from Finesse hosts and restrict it to known-required destinations using network segmentation.
• Track the EPSS exploitation probability for this CVE, which currently indicates elevated likelihood of attempted exploitation in the wild.

How to Mitigate CVE-2024-20404

Immediate Actions Required

• Apply the fixed software releases identified in the Cisco Security Advisory for Cisco Finesse 11.6(1) and 12.6(2).
• Restrict network access to the Finesse web-based management interface so it is reachable only from trusted administrative networks.
• Audit outbound network policy from Finesse hosts to block access to cloud metadata services and unrelated internal management planes.

Patch Information

Cisco has released fixed software addressing this vulnerability. Refer to the Cisco Security Advisory cisco-sa-finesse-ssrf-rfi-Um7wT8Ew for the specific fixed release versions and upgrade guidance. No workarounds are listed by the vendor; upgrading to a fixed release is the required remediation path.

Workarounds

• Cisco has not published a configuration workaround. Network-level controls such as access control lists and segmentation should be used as compensating measures until patching is complete.
• Place the Finesse management interface behind a reverse proxy or jump host that enforces authentication and source IP restrictions.
• Implement egress filtering on the Finesse appliance to deny outbound requests to internal address ranges and metadata IPs.

# Example egress restriction using iptables on the Finesse host
# Block outbound HTTP/HTTPS to cloud metadata and link-local addresses
iptables -A OUTPUT -d 169.254.169.254 -j DROP
iptables -A OUTPUT -d 127.0.0.0/8 -p tcp --dport 80 -j DROP
iptables -A OUTPUT -d 10.0.0.0/8 -p tcp --dport 8080 -j DROP