CVE-2007-1991 in CmailServer
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in mail/signup.asp in CmailServer WebMail 5.4.3, and possibly earlier, allows remote attackers to inject arbitrary web script or HTML via the Comment parameter, a different vector than CVE-2007-1927.
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Analysis
by VulDB Data Team • 08/28/2018
The vulnerability identified as CVE-2007-1991 represents a cross-site scripting flaw within the CmailServer WebMail 5.4.3 application specifically affecting the mail/signup.asp component. This issue falls under the broader category of web application security weaknesses that enable malicious actors to execute arbitrary code within the context of a victim's browser session. The vulnerability is particularly concerning as it demonstrates how seemingly benign user input fields can become attack vectors for sophisticated web-based assaults. The flaw exists in the application's input validation mechanisms, where user-supplied data from the Comment parameter is not properly sanitized before being rendered back to users. This creates an opportunity for attackers to inject malicious scripts that can persist and execute whenever other users view the affected content, making it a classic persistent XSS vulnerability that can compromise user sessions and data integrity.
The technical implementation of this vulnerability stems from inadequate sanitization of user input within the signup process. When users submit comments through the mail/signup.asp page, the application fails to properly encode or filter special characters that could be interpreted as HTML or JavaScript commands. The Comment parameter serves as the primary attack vector, allowing an attacker to embed malicious payloads that exploit the browser's interpretation of HTML content. This vulnerability is classified under CWE-79, which specifically addresses Cross-Site Scripting flaws in web applications. The attack typically involves encoding malicious JavaScript within the comment field using techniques such as HTML entity encoding or direct script injection, which then executes when other users browse the affected page. The vulnerability operates outside the scope of CVE-2007-1927, indicating a distinct code path or implementation flaw that requires separate remediation approaches.
The operational impact of CVE-2007-1991 extends beyond simple data theft or session hijacking, as it can enable more sophisticated attack chains within the webmail environment. Successful exploitation allows attackers to access user emails, modify account settings, steal authentication tokens, and potentially escalate privileges within the webmail system. The persistent nature of this vulnerability means that once injected, malicious scripts can affect multiple users over extended periods, making detection and remediation more challenging. From an attacker's perspective, this vulnerability aligns with ATT&CK technique T1531 for "Account Access Removal" and T1566 for "Phishing" when used in conjunction with social engineering campaigns. The vulnerability can be leveraged to create convincing phishing pages that appear legitimate within the webmail interface, potentially bypassing user security awareness and organizational controls. Organizations relying on CmailServer WebMail 5.4.3 face significant risk exposure, as this flaw can facilitate unauthorized access to sensitive email communications and compromise the confidentiality of user data.
Mitigation strategies for CVE-2007-1991 require immediate implementation of proper input validation and output encoding mechanisms. Organizations should implement comprehensive HTML sanitization routines that strip or encode dangerous characters from user input before processing or storing the data. The most effective approach involves adopting a whitelist-based input validation strategy that only permits known safe characters and patterns within the Comment field. Additionally, implementing proper Content Security Policy headers can provide an additional layer of defense against script execution. Security patches or upgrades to newer versions of CmailServer WebMail should be prioritized, as the vulnerability affects versions 5.4.3 and potentially earlier releases. Regular security testing including dynamic application security testing and manual penetration testing should be conducted to identify similar vulnerabilities in other application components. Network monitoring and log analysis should be enhanced to detect suspicious input patterns and potential exploitation attempts. The remediation process should also include user education regarding the risks of clicking on suspicious links or entering untrusted content in webmail applications, as this vulnerability can be effectively exploited through social engineering approaches that manipulate user behavior.