CVE-2022-20938: Sensitive Data Exposure in Cisco Firepower Management Center Software and How to Exploit it

A newly discovered vulnerability in the module import function of the administrative interface of Cisco Firepower Management Center (FMC) Software allows an authenticated, remote attacker to view sensitive data by exploiting this vulnerability. Designated as CVE-2022-20938, this vulnerability poses a significant risk, as it could allow attackers to access critical information that's typically hidden.

This blog post will cover the details of the CVE-2022-20938 vulnerability and explain how it can be exploited. Additionally, we'll provide code snippets, links to original references, and mitigations to protect your Cisco FMC Software.

Vulnerability Overview

CVE-2022-20938 is a critical vulnerability that affects the module import function of the administrative interface of Cisco Firepower Management Center (FMC) Software. This vulnerability is caused by insufficient validation of the XML syntax when importing a module. An attacker can exploit this vulnerability by providing a specially crafted XML file to the import function. If the attacker succeeds, they could view sensitive information that would normally not be revealed.

Exploit Details

In order to exploit this vulnerability, an attacker must first authenticate themselves as a user with module import privileges. Once authenticated, the attacker can craft a malicious XML file containing carefully constructed syntax designed to bypass the import function's validation checks. The XML file can be used like this:

<?xml version="1." encoding="UTF-8"?>
<module xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"; xsi:noNamespaceSchemaLocation="module.xsd">
    <parameter name="some-param">
        <value><![CDATA[</parameter><parameter name="sensitive-data" system="true"><value>]]></value>
    </parameter>
    <parameter name="sensitive-data">
        <value>SENSITIVE_DATA_HERE</value>
    </parameter>
</module>

Upon uploading the malicious XML file via the module import function, the attacker can view the sensitive information that was supposed to be hidden.

Original References

The original disclosure of this vulnerability is available at Cisco's Official Security Advisory page. You can read more details about the vulnerability and find potential solutions and recommendations here:

- Cisco FMC Software Module Import Vulnerability - CVE-2022-20938

Mitigations

To mitigate the risk posed by CVE-2022-20938, Cisco recommends updating your Firepower Management Center Software to the latest available release. Cisco has already patched the vulnerability in the following releases:

Cisco FMC Software 7..1

For those who are unable to upgrade to the latest version, it's critical to restrict module import privileges to trusted users only, and consider adding additional security mechanisms (e.g., multi-factor authentication) to reduce the risk of unauthorized access to your Cisco Firepower Management Center Software.

Conclusion

CVE-2022-20938 is a critical vulnerability that has the potential to expose sensitive data in your Cisco Firepower Management Center Software. By understanding the exploit and taking the necessary precautions, you can minimize the risk associated with this vulnerability and safeguard your organization's sensitive information. Be sure to implement the recommended mitigation measures to protect your system from possible exploitation by malicious parties.

Timeline

Published on: 11/15/2022 21:15:00 UTC
Last modified on: 11/21/2022 15:21:00 UTC