CVE-2017-17752 in Ability Mail Server
Summary
by MITRE
Ability Mail Server 3.3.2 has Cross Site Scripting (XSS) via the body of an e-mail message, with JavaScript code executed on the Read Mail screen (aka the /_readmail URI). This is fixed in version 4.2.4.
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Analysis
by VulDB Data Team • 06/29/2025
The vulnerability identified as CVE-2017-17752 affects Ability Mail Server version 3.3.2 and represents a critical cross site scripting flaw that enables attackers to execute malicious javascript code within the target environment. This vulnerability specifically manifests when email messages containing malicious javascript payloads are processed by the mail server and subsequently displayed on the Read Mail screen, which is accessible via the /_readmail URI endpoint. The flaw resides in the server's insufficient input validation and output encoding mechanisms that fail to properly sanitize user-supplied content before rendering it within the web interface.
The technical implementation of this vulnerability stems from the mail server's failure to adequately filter or escape special characters in email body content before displaying it to users. When a victim accesses the read mail screen, the server renders the email content without proper sanitization, allowing javascript code embedded within the message body to execute in the context of the victim's browser session. This creates a persistent cross site scripting vector that can be exploited by remote attackers who have access to send emails to the target system. The vulnerability is classified under CWE-79 as Improper Neutralization of Input During Web Page Generation, which specifically addresses the failure to properly sanitize user input that gets rendered in web contexts.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to perform a wide range of malicious activities including session hijacking, credential theft, and redirection to malicious websites. An attacker could craft a specially formatted email message containing javascript that steals cookies or session tokens from authenticated users, potentially allowing complete compromise of user accounts. The vulnerability also aligns with ATT&CK technique T1566.001 which covers Spearphishing Attachment, where attackers use malicious email attachments or content to deliver payloads that exploit web application vulnerabilities. The fact that this vulnerability is present in version 3.3.2 but fixed in 4.2.4 indicates that the vendor recognized the severity of the issue and implemented proper input sanitization measures in the newer release.
Organizations utilizing Ability Mail Server version 3.3.2 should immediately implement mitigations including upgrading to version 4.2.4 or later, which contains the necessary security patches. Additionally, administrators should consider implementing additional protective measures such as web application firewalls that can detect and block suspicious javascript patterns in email content, and implementing strict email filtering rules that scan for potentially malicious content. The vulnerability demonstrates the critical importance of proper input validation and output encoding in web applications, particularly those handling user-generated content. Organizations should also establish robust patch management processes to ensure timely deployment of security updates and maintain awareness of similar vulnerabilities in other mail server implementations that may present similar attack vectors.