CVE-2006-0842 in @Mail Webmail System
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Calacode @Mail 4.3 allows remote attackers to inject arbitrary web script or HTML via a modified javascript: string in the SRC attribute of an IMG element in an e-mail message, as demonstrated by "java	script:." NOTE: the provenance of this information is unknown; the details are obtained solely from third party information.
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Analysis
by VulDB Data Team • 08/05/2017
This cross-site scripting vulnerability exists in Calacode @Mail version 4.3, representing a critical security flaw that enables remote attackers to execute malicious scripts within victim browsers. The vulnerability specifically targets the email client's handling of image source attributes, where an attacker can craft malicious email content containing a modified javascript: string within the SRC attribute of an IMG element. The attack vector demonstrates the use of "java	script:" as a technique to bypass certain input validation mechanisms, exploiting the client-side processing of email content. This particular variant utilizes HTML entity encoding to obfuscate the javascript protocol, making the attack more stealthy and potentially bypassing basic security filters. The vulnerability stems from insufficient sanitization of user-provided content during email rendering, allowing malicious code execution when users view infected email messages.
The technical implementation of this XSS flaw occurs at the application layer where Calacode @Mail processes email content without proper input validation or output encoding for image source attributes. When the email client renders an HTML email containing an IMG element with a malicious SRC attribute, the application fails to properly sanitize or escape the javascript: protocol reference, allowing the browser to interpret and execute the embedded script. This represents a classic reflected XSS vulnerability where the malicious payload is embedded within the email message itself rather than being passed through URL parameters or form fields. The vulnerability operates under CWE-79 which categorizes cross-site scripting flaws as weaknesses in input validation and output encoding, specifically targeting the failure to properly escape or validate user-supplied data before rendering it in a web context.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable sophisticated attacks including session hijacking, credential theft, and redirection to malicious websites. An attacker could craft emails that, when viewed by victims, automatically execute scripts to steal cookies, capture login credentials, or redirect users to phishing sites. The remote nature of this attack means that victims need only view the malicious email in their email client to be compromised, making it particularly dangerous for enterprise environments where users may inadvertently click on or view infected emails. The vulnerability affects the email client's security model by undermining the trust boundary between the email content and the user's browser environment, effectively allowing attackers to execute arbitrary code within the context of the user's session.
Mitigation strategies for this vulnerability should focus on implementing robust input validation and output encoding mechanisms within the email client. Organizations should immediately update to patched versions of Calacode @Mail or implement network-level filtering to block suspicious email content containing javascript: protocols in image source attributes. The solution should include proper HTML sanitization of email content, implementing Content Security Policy headers, and employing sandboxing techniques to isolate potentially malicious content. Security measures should also incorporate regular security assessments of email clients and web-based applications to identify similar vulnerabilities, following ATT&CK framework techniques for credential access and defense evasion. Additionally, user education about suspicious email content and implementing email security gateways that can detect and block such obfuscated javascript payloads would significantly reduce the risk of exploitation.