CVE-2020-5540 in CyberMail
Summary
by MITRE
Cross-site scripting vulnerability in CyberMail Ver.6.x and Ver.7.x allows remote attackers to inject arbitrary script or HTML via a specially crafted URL.
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Analysis
by VulDB Data Team • 08/25/2020
The vulnerability identified as CVE-2020-5540 represents a critical cross-site scripting flaw affecting CyberMail versions 6.x and 7.x. This security weakness resides in the application's handling of user-supplied input within URL parameters, creating an avenue for remote attackers to execute malicious scripts in the context of a victim's browser. The vulnerability stems from insufficient input validation and output encoding mechanisms within the web application's processing pipeline, allowing attackers to craft malicious URLs that bypass security controls designed to prevent code injection.
The technical exploitation of this vulnerability occurs when a user clicks on a maliciously crafted URL containing script code or HTML payload. The vulnerable application fails to properly sanitize or escape the input data before rendering it in the user interface, resulting in the execution of unauthorized code within the victim's browser session. This flaw operates at the application layer and can be leveraged to perform various malicious activities including session hijacking, data theft, or redirection to malicious websites. The vulnerability is classified as CWE-79 - Improper Neutralization of Input During Web Page Generation, which directly maps to the common web application security weakness of inadequate input validation and output encoding practices.
From an operational impact perspective, this XSS vulnerability poses significant risks to organizations using CyberMail versions 6.x and 7.x. Attackers can exploit this weakness to steal user session cookies, potentially gaining unauthorized access to email accounts and sensitive communications. The vulnerability also enables the execution of malicious scripts that could redirect users to phishing sites, install malware, or perform actions on behalf of authenticated users without their knowledge. The remote nature of the attack means that exploitation does not require physical access to the target system and can be executed from anywhere on the internet, making it particularly dangerous for organizations with remote workers or public-facing email services.
Security professionals should prioritize immediate mitigation of this vulnerability through proper input validation and output encoding implementations. The recommended approach includes implementing strict input sanitization routines that filter or escape potentially dangerous characters and patterns in URL parameters before processing. Organizations should also deploy comprehensive web application firewalls and content security policies to detect and prevent malicious script execution. Additionally, regular security assessments and vulnerability scanning should be conducted to identify similar weaknesses in other web applications. The ATT&CK framework categorizes this type of vulnerability under T1203 - Exploitation for Client Execution, highlighting the need for layered defensive measures including network segmentation, user education, and monitoring for suspicious URL patterns. Organizations must also consider implementing automated patch management processes to ensure timely remediation of such vulnerabilities across their infrastructure.
The exploitation of this vulnerability demonstrates the critical importance of proper input validation in web applications and aligns with industry best practices outlined in OWASP Top Ten 2017 and the CWE hierarchy. This vulnerability serves as a reminder that even seemingly simple input handling can create significant security risks when proper sanitization measures are not implemented, emphasizing the need for comprehensive security testing and code review processes throughout the software development lifecycle.