A critical security vulnerability, identified as CVE-2022-20917, has been discovered in the Extensible Messaging and Presence Protocol (XMPP) message processing feature of Cisco Jabber. This vulnerability could potentially allow an authenticated, remote attacker to manipulate the content of XMPP messages that are used by the affected application. The issue is due to the improper handling of nested XMPP messages within requests that are sent to the vulnerable Cisco Jabber client software.

In this post, we will discuss the details of this vulnerability, the steps to exploit it, available references for further understanding, and recommended mitigation strategies.

Exploit Details

The exploit involves an attacker connecting to an XMPP messaging server and sending specially crafted XMPP messages to affected Cisco Jabber client software. If successful, the attacker could manipulate the content of XMPP messages and potentially coerce the Jabber client application into performing unsafe actions.

How does this work?
The vulnerability lies in the way Cisco Jabber handles nested XMPP messages within requests that are sent to the client software. The application fails to properly sanitize and validate these messages, therefore allowing malicious inputs to be processed. An attacker can exploit this weakness by sending specially crafted XMPP messages containing nested elements to the vulnerable client, leading to undesired behavior or manipulation of the message content.

Here is a code snippet illustrating a potential exploit

x = '<?xml version="1." encoding="UTF-8"?>' \
    + '<stream:stream to="Your-Domain" xmlns="jabber:client" xmlns:stream="http://etherx.jabber.org/streams"; version="1.">' \
    + '<message to="victim@Your-Domain" type="chat">' \
    + '<body>' \
    + '<![CDATA[<img src="x" onerror="%s"%2F>]]>' \
    + '</body>' \
    + '</message>' \
    + '</stream>'

The above code snippet demonstrates how a malicious actor could create an XMPP message with a nested HTML element designed to exploit the vulnerability. In this case, an image tag with a non-existent source ('x') is used, and an 'onerror' event is attached to execute malicious JavaScript when the image fails to load.

Original References

- Cisco Advisory: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-jabber-89GkbGNc
- NVD (National Vulnerability Database): https://nvd.nist.gov/vuln/detail/CVE-2022-20917
- XMPP (Extensible Messaging and Presence Protocol): https://xmpp.org/about/technology-overview.html

Update Cisco Jabber client software

The most effective way to address this vulnerability is by updating your Cisco Jabber client software to the latest version, which contains necessary patches and security updates.

Use a secure XMPP server

Ensure that your organization is using a secure and properly configured XMPP server to prevent unauthorized access and help mitigate the risks associated with vulnerabilities like this.

Implement strong authentication and access control measures

To reduce the likelihood of an attacker gaining access to your XMPP messaging server, implement strong authentication and access control measures to prevent unauthorized entities from connecting.

Educate users about safe browsing habits

Inform users about the dangers of clicking on suspicious links or interacting with potentially malicious XMPP messages. Emphasize the importance of carefully examining message content and sender information before taking action.

Conclusion

CVE-2022-20917 is a serious vulnerability in Cisco Jabber's XMPP message processing feature that could allow an attacker to manipulate message content and cause the client application to perform unsafe actions. It is essential that organizations update their software and implement measures to reduce the risk of exploitation. By reviewing the provided information and taking appropriate steps, you can protect your organization from being impacted by this vulnerability.

Timeline

Published on: 09/15/2023 03:15:00 UTC
Last modified on: 09/21/2023 14:50:00 UTC