CVE-2011-3635 in empathy
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the theme_adium_append_message function in empathy-theme-adium.c in the Adium theme in libempathy-gtk in Empathy 3.2.1 and earlier allows remote attackers to inject arbitrary web script or HTML via a crafted alias (aka nickname).
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 11/24/2021
The CVE-2011-3635 vulnerability represents a classic cross-site scripting flaw that existed within the Empathy instant messaging client's graphical user interface components. This vulnerability specifically affected the theme_adium_append_message function in the empathy-theme-adium.c file, which was part of the libempathy-gtk library used by the Empathy 3.2.1 and earlier versions. The flaw emerged from insufficient input validation and sanitization mechanisms within the Adium theme implementation, creating a pathway for malicious actors to execute arbitrary code within the context of a victim's browser session.
The technical nature of this vulnerability stems from the improper handling of user-provided data, specifically crafted aliases or nicknames that users might encounter in chat conversations. When the empathy-theme-adium.c component processed these aliases, it failed to properly escape or filter special characters that could be interpreted as HTML or JavaScript code. This omission allowed attackers to craft malicious nicknames containing script tags or other executable content that would be rendered directly in the user interface without proper sanitization. The vulnerability falls under the CWE-79 category of Cross-Site Scripting, which is a fundamental weakness in web applications and GUI frameworks that fails to properly validate or escape user input before rendering it in the interface.
The operational impact of this vulnerability was significant for users of the Empathy instant messaging client, particularly in environments where users might interact with untrusted parties. Attackers could exploit this flaw by simply sending a chat message with a maliciously crafted nickname that would execute upon display in the user's interface. This could lead to session hijacking, credential theft, or redirection to malicious websites. The vulnerability was particularly dangerous because it required no special privileges or complex attack vectors - simply receiving a message with a crafted alias was sufficient to trigger the exploit. According to ATT&CK framework, this vulnerability maps to T1566 (Phishing) and T1059 (Command and Scripting Interpreter) techniques, as attackers could use it to execute malicious scripts in the victim's browser context.
The remediation for CVE-2011-3635 required updating the Empathy client to versions that properly sanitized user input before rendering it in the graphical interface. This involved implementing proper HTML escaping mechanisms within the theme_adium_append_message function to ensure that any special characters in nicknames were properly encoded before display. System administrators and users needed to upgrade to Empathy 3.2.2 or later versions where this vulnerability was patched. Organizations using the affected software should have implemented network monitoring to detect unusual chat traffic patterns and user behavior that might indicate exploitation attempts. The vulnerability highlighted the importance of input validation in GUI applications and demonstrated how seemingly innocuous user interface elements could become attack vectors when proper security controls were not implemented. Security practitioners should have emphasized the need for comprehensive testing of user interface components, particularly those handling external input, as part of their vulnerability assessment processes.