CVE-2015-8807 in Groupware Webmail Edition
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the _renderVarInput_number function in horde/framework/Core/lib/Horde/Core/Ui/VarRenderer/Html.php in Horde Groupware before 5.2.12 and Horde Groupware Webmail Edition before 5.2.12 allows remote attackers to inject arbitrary web script or HTML via vectors involving numeric form fields.
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Analysis
by VulDB Data Team • 07/24/2022
The CVE-2015-8807 vulnerability represents a critical cross-site scripting flaw discovered in the Horde Groupware web application suite, specifically within the _renderVarInput_number function located in the file horde/framework/Core/lib/Horde/Core/Ui/VarRenderer/Html.php. This vulnerability affects versions prior to 5.2.12 of both Horde Groupware and Horde Groupware Webmail Edition, creating a significant security risk for organizations relying on these applications for email and groupware services. The flaw resides in how the application handles numeric form fields during user interface rendering, allowing malicious actors to inject arbitrary web scripts or HTML content through carefully crafted input vectors.
The technical implementation of this vulnerability stems from inadequate input validation and output sanitization within the numeric form field rendering mechanism. When the _renderVarInput_number function processes numeric inputs, it fails to properly escape or filter special characters that could be interpreted as HTML or JavaScript code. This insufficient sanitization creates an opening for attackers to inject malicious payloads directly into numeric form fields, which are then rendered back to users without proper encoding. The vulnerability specifically targets the HTML rendering process where numeric inputs are converted into form elements, making it particularly dangerous as it can affect any application component that utilizes numeric form fields for user data entry.
The operational impact of CVE-2015-8807 extends beyond simple script injection, as it can enable attackers to execute arbitrary code within the context of a victim's browser session. This capability allows for session hijacking, credential theft, data exfiltration, and the potential for privilege escalation within the affected applications. Attackers can craft malicious numeric inputs that, when processed by the vulnerable function, execute scripts that can redirect users to phishing sites, steal authentication tokens, or modify application behavior. The vulnerability is particularly concerning in groupware environments where users frequently interact with numeric data such as phone numbers, quantities, or other numerical inputs, making it a persistent threat across various business applications.
Organizations affected by this vulnerability should prioritize immediate remediation through the installation of patches released in Horde Groupware versions 5.2.12 and 5.2.12 for Webmail Edition. The mitigation strategy should include comprehensive testing of the patched environment to ensure no regression issues affect existing functionality. Security teams should also implement additional monitoring and logging mechanisms to detect potential exploitation attempts, particularly focusing on unusual numeric input patterns that might indicate malicious activity. This vulnerability aligns with CWE-79, which categorizes cross-site scripting flaws, and can be mapped to ATT&CK technique T1566.001 for credential access through spearphishing attachments, as the XSS capability enables more sophisticated attack vectors. Organizations should also consider implementing web application firewalls and content security policies as additional defensive measures to protect against similar vulnerabilities in their web applications.