CVE-2016-6853 in OX Guard
Summary
by MITRE
An issue was discovered in Open-Xchange OX Guard before 2.4.2-rev5. Script code and references to external websites can be injected to the names of PGP public keys. When requesting that key later on using a specific URL, such script code might get executed. In case of injecting external websites, users might get lured into a phishing scheme. Malicious script code can be executed within a user's context. This can lead to session hijacking or triggering unwanted actions via the web interface (sending mail, deleting data etc.).
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Analysis
by VulDB Data Team • 12/08/2024
The vulnerability identified as CVE-2016-6853 represents a critical cross-site scripting flaw within Open-Xchange OX Guard versions prior to 2.4.2-rev5. This security weakness stems from inadequate input validation mechanisms that fail to properly sanitize user-supplied data when processing PGP public key names. The flaw creates a pathway for malicious actors to inject arbitrary script code and external website references directly into the key naming system, fundamentally undermining the application's security posture. The vulnerability operates at the application layer and specifically targets the PGP key management functionality, making it particularly dangerous for organizations relying on email encryption and security protocols.
The technical exploitation of this vulnerability occurs when a user requests a PGP public key through a specifically crafted URL that contains the injected malicious code. This injection point allows attackers to execute scripts within the context of the victim's browser session, effectively bypassing traditional security boundaries. The flaw enables attackers to manipulate the application's behavior by injecting code that executes in the user's browser, creating a persistent threat vector that can be leveraged for various malicious activities. The vulnerability's impact extends beyond simple code execution to include sophisticated phishing schemes that can deceive users into revealing sensitive information or performing unintended actions through the compromised web interface.
The operational consequences of CVE-2016-6853 are severe and multifaceted, encompassing both immediate and long-term security implications. Users may unknowingly execute malicious scripts that can hijack their active sessions, potentially leading to unauthorized access to sensitive email communications and data. The vulnerability also enables attackers to trigger unwanted actions within the web interface, including sending emails on behalf of users, deleting critical data, or modifying system configurations. This makes the flaw particularly dangerous in enterprise environments where email security is paramount and where users may have elevated privileges within the system. The phishing component of the vulnerability adds an additional layer of sophistication, as attackers can craft convincing deceptive interfaces that appear legitimate to unsuspecting users.
Organizations affected by this vulnerability should prioritize immediate remediation through the application of the vendor-provided patch version 2.4.2-rev5, which addresses the input validation shortcomings that enable the injection attack. System administrators must conduct comprehensive security assessments to identify any potential exploitation that may have occurred prior to patch deployment, including monitoring for unusual user activities or unauthorized email actions. The remediation process should also include reviewing and strengthening input validation mechanisms throughout the application, particularly in areas where user-supplied data is processed and stored. Additionally, organizations should implement enhanced monitoring of PGP key management activities and consider deploying web application firewalls to detect and prevent similar injection attacks. This vulnerability aligns with CWE-79 Cross-site Scripting and follows ATT&CK techniques related to privilege escalation and credential access through web-based attacks. The incident underscores the importance of proper input sanitization and the potential for seemingly benign functionality to become attack vectors when inadequate security controls are in place.