CVE-2017-7855 in Icewarp
Summary
by MITRE
In the webmail component in IceWarp Server 11.3.1.5, there was an XSS vulnerability discovered in the "language" parameter.
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Analysis
by VulDB Data Team • 11/25/2019
The vulnerability identified as CVE-2017-7855 represents a cross-site scripting flaw within the webmail component of IceWarp Server version 11.3.1.5. This issue specifically affects the handling of user input through the "language" parameter, which is utilized to determine the interface language for webmail users. The vulnerability stems from insufficient input validation and output encoding mechanisms that fail to properly sanitize user-supplied data before incorporating it into web responses. This weakness allows malicious actors to inject arbitrary JavaScript code into the application's response, potentially compromising user sessions and enabling unauthorized access to sensitive email data.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious payload containing JavaScript code and submits it through the vulnerable "language" parameter. When the webmail application processes this input without proper sanitization, the injected script executes within the context of the victim's browser session. This type of flaw falls under CWE-79 which specifically addresses cross-site scripting vulnerabilities where untrusted data is improperly incorporated into web pages without adequate validation or encoding. The vulnerability demonstrates a classic case of insufficient output escaping, where the application fails to encode special characters that could alter the intended execution context of web content.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to perform session hijacking, steal authentication cookies, and access user email accounts containing potentially sensitive information. Attackers could leverage this vulnerability to redirect users to malicious websites, inject malicious content into email communications, or even establish persistent backdoors through the compromised webmail interface. The vulnerability affects all users of the IceWarp Server webmail component who are authenticated and actively using the application, making it particularly dangerous in enterprise environments where email systems serve as primary communication channels. This weakness also aligns with ATT&CK technique T1566 which covers social engineering attacks through malicious email content, potentially allowing attackers to escalate privileges and gain broader system access.
Mitigation strategies for CVE-2017-7855 should focus on implementing proper input validation and output encoding mechanisms throughout the application. Organizations should immediately apply the vendor-supplied patch or upgrade to a version of IceWarp Server that addresses this vulnerability. Additionally, implementing content security policies can provide an additional layer of protection against script injection attacks. Security measures should include validating all user inputs against a strict whitelist of acceptable language codes, implementing proper HTML encoding for all dynamic content, and regularly auditing application code for similar vulnerabilities. Network-level protections such as web application firewalls can also help detect and block malicious payloads attempting to exploit this vulnerability, though they should not be considered a substitute for proper application-level fixes. The remediation process should include comprehensive testing to ensure that the fix does not introduce regressions in legitimate functionality while maintaining the application's core features.