CVE-2017-5603 in Jitsi
Summary
by MITRE
An incorrect implementation of "XEP-0280: Message Carbons" in multiple XMPP clients allows a remote attacker to impersonate any user, including contacts, in the vulnerable application's display. This allows for various kinds of social engineering attacks. This CVE is for Jitsi 2.5.5061 - 2.9.5544.
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Analysis
by VulDB Data Team • 11/12/2022
The vulnerability described in CVE-2017-5603 represents a critical implementation flaw in the XMPP protocol's Message Carbons extension as implemented in Jitsi versions ranging from 2.5.5061 through 2.9.5544. Message Carbons, defined by XEP-0280, are designed to enable users to receive copies of all messages sent to their other connected resources, effectively providing message synchronization across devices. However, the implementation in these Jitsi versions contained a fundamental security defect that allowed attackers to manipulate message display behavior. This flaw specifically affected how the client processed incoming carbon copies, creating a window where malicious actors could inject crafted messages that would appear to originate from legitimate users within the contact list.
The technical nature of this vulnerability stems from improper validation of message source identification within the carbon copy processing logic. When the vulnerable Jitsi client received message carbons, it failed to adequately authenticate the origin of the message or properly verify that the displayed sender information matched the actual message source. This implementation error falls under CWE-284, Access Control, as it allowed unauthorized modification of message display properties without proper authorization mechanisms. The flaw essentially created a trust boundary violation where the client's user interface could be manipulated to show false sender information, making it appear as though messages were coming from legitimate contacts rather than from an attacker.
The operational impact of this vulnerability extends far beyond simple display manipulation, creating significant opportunities for social engineering attacks that could compromise user trust and system integrity. An attacker could craft malicious messages that would appear to originate from any user in the victim's contact list, including trusted contacts, thereby bypassing normal security expectations and user skepticism. This capability enabled sophisticated phishing attacks where users might be tricked into believing they were receiving legitimate communications from colleagues, friends, or family members. The vulnerability particularly affected collaborative environments where users rely on message authenticity for security decisions, potentially allowing attackers to manipulate communication flows and gain unauthorized access to sensitive information or systems through deception rather than direct technical exploitation.
Mitigation strategies for this vulnerability required immediate patching of affected Jitsi versions to correct the message carbon processing implementation. Organizations should have implemented network monitoring to detect anomalous message patterns that might indicate exploitation attempts, particularly focusing on unusual message flow behaviors that could suggest carbon manipulation. The fix involved strengthening the authentication and validation mechanisms within the carbon processing code to ensure that displayed sender information matched verified message sources. Additionally, users should have been educated about the potential for display manipulation and encouraged to verify message authenticity through alternative means, though this represents a workaround rather than a proper fix. This vulnerability highlights the importance of proper implementation of security protocols and the potential for seemingly benign features to introduce significant security risks when not properly validated against malicious input. The incident also demonstrates the necessity of thorough security testing for protocol extensions, particularly those that modify user interface behavior and trust relationships within communication systems.