CVE-2024-20497: Medium Vulnerability in Cisco Expressway Edge

A vulnerability in Cisco Expressway Edge (Expressway-E) could allow an authenticated, remote attacker to masquerade as another user on an affected system. This vulnerability is due to inadequate authorization checks for Mobile and Remote Access (MRA) users. An attacker could exploit this vulnerability by running a series of crafted commands. A successful exploit could allow the attacker to intercept calls that are destined for a particular phone number or to make phone calls and have that phone number appear on the caller ID. To successfully exploit this vulnerability, the attacker must be an MRA user on an affected system.

The severity of this vulnerability is classified as medium, with a CVSS score of 4.3. This indicates that while the risk is not critical, it poses a significant threat to organizations that rely on Cisco Expressway Edge for secure communication. Organizations should prioritize patching immediately to mitigate the risks associated with this flaw.

Currently, there is no known public exploit available for this vulnerability, and it has not been included in the Known Exploited Vulnerabilities (KEV) catalog. However, the potential impact of successful exploitation makes it essential for organizations to remain vigilant.

Organizations are advised to address this vulnerability as part of their priority patch cycle to ensure the security of their communication systems.

Vulnerability Details

A vulnerability in Cisco Expressway Edge (Expressway-E) could allow an authenticated, remote attacker to masquerade as another user on an affected system. This vulnerability is due to inadequate authorization checks for Mobile and Remote Access (MRA) users. An attacker could exploit this vulnerability by running a series of crafted commands. A successful exploit could allow the attacker to intercept calls that are destined for a particular phone number or to make phone calls and have that phone number appear on the caller ID. To successfully exploit this vulnerability, the attacker must be an MRA user on an affected system.

The CVSS score for this vulnerability is 4.3, indicating a medium severity. The attack vector is classified as NETWORK, with low attack complexity and low privileges required for exploitation. The confidentiality impact is none, while there is a low integrity impact and no availability impact.

Technical Analysis

The root cause of this vulnerability is the inadequate authorization checks for Mobile and Remote Access (MRA) users. The attack vector is network-based, allowing remote attackers to exploit the vulnerability without physical access to the systems.

The attack complexity is low, as it does not require advanced skills or resources to exploit. The privileges required to exploit this vulnerability are also low, meaning that an attacker with basic access can potentially execute the attack. User interaction is not required, making the vulnerability even easier to exploit.

In terms of impact, there is no confidentiality impact, which means that sensitive information is not directly exposed. However, there is a low integrity impact, allowing attackers to manipulate the system to some extent, such as altering caller ID information.

Risk & Impact Analysis

Risk to organizations includes potential unauthorized access to communication systems and the ability to manipulate call information, which could lead to trust issues and reputational damage. The blast radius for this vulnerability is significant, as it can affect any organization using Cisco Expressway Edge for voice communications.

Given the CVSS score of 4.3 and the fact that it is not included in the KEV catalog, organizations should still treat this vulnerability with urgency. Organizations should address in priority patch cycle to mitigate the risks associated with this vulnerability.

Exploitation Status

Affected Versions

The affected version of Cisco Expressway Edge includes all versions prior to 15.2. Organizations should verify their systems to ensure they are not running vulnerable versions.

Mitigation & Remediation

Organizations should apply the latest patches provided by Cisco for the Expressway Edge product. Ensure that all instances are upgraded to version 15.2 or later to mitigate this vulnerability. Additionally, organizations should review their authorization checks for MRA users to ensure they are robust against potential exploitation.

For further guidance, organizations can refer to the penetration testing services offered to assess their security posture and identify any additional vulnerabilities.

Detection Guidance

Organizations should monitor logs for any unusual access patterns or unauthorized commands executed by MRA users. Additionally, they should implement network intrusion detection systems to identify suspicious activities related to this vulnerability.

AppSecure Threat Intelligence Insight

The long-term significance of this vulnerability underscores the importance of robust authorization checks in communication systems. Organizations are reminded that even medium-severity vulnerabilities can lead to severe consequences if left unaddressed.

This vulnerability represents a pattern of insufficient authorization mechanisms being exploited in various systems, highlighting the need for ongoing security assessments. Security teams should learn from such incidents to improve their defensive strategies.

Strategically, organizations should adopt a proactive approach to security by implementing regular security assessments and enhancing their overall security posture. For further information on enhancing security measures, organizations may refer to the penetration testing methodology and the importance of vulnerability management programs.

Organizations are encouraged to continuously monitor for similar vulnerabilities and engage in security best practices to safeguard their systems against potential threats.