CVE-2019-9882 in MailSherlock MSR35
Summary
by MITRE
Multi modules of MailSherlock MSR35 and MSR45 lead to a CSRF vulnerability. It allows attacker to add malicious email sources into whitelist via user/save_list.php?ACSION=&type=email&category=white&locate=big5&cmd=add&[email protected]&new_memo=&add=%E6%96%B0%E5%A2%9E without any authorizes.
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Analysis
by VulDB Data Team • 09/26/2023
The CVE-2019-9882 vulnerability affects multiple modules within the MailSherlock MSR35 and MSR45 email security appliances, representing a critical cross-site request forgery flaw that undermines the security posture of these network protection devices. This vulnerability resides in the web-based administrative interface of the appliances, specifically within the user management functionality at the endpoint user/save_list.php. The flaw allows unauthenticated attackers to manipulate the email whitelist configuration by exploiting the lack of proper authorization checks and anti-CSRF mechanisms. The vulnerability is particularly concerning because it enables attackers to inject malicious email addresses into the whitelist without requiring any valid credentials or authentication, effectively bypassing the appliance's built-in email filtering and security controls. The attack vector is facilitated through a direct HTTP request that includes parameters for adding new email addresses to the whitelist, with the malicious email address being [email protected] in the provided example. This vulnerability directly maps to CWE-352, which defines Cross-Site Request Forgery as a weakness where the application fails to validate that requests originate from legitimate sources, and aligns with ATT&CK technique T1078.004 for Valid Accounts and T1566.001 for Phishing, as it enables attackers to establish persistence and deliver malicious emails through compromised whitelist entries. The operational impact of this vulnerability is severe as it allows attackers to establish a persistent backdoor within the email security infrastructure, potentially enabling them to bypass email filtering, deliver phishing emails, or exfiltrate sensitive information through the compromised whitelist entries. The vulnerability affects the integrity and availability of the email security appliance by allowing unauthorized modification of critical security policies, potentially leading to data breaches, unauthorized access, and the compromise of email communications within the protected network. The lack of authorization checks and anti-CSRF tokens in the user/save_list.php endpoint represents a fundamental flaw in the application's security architecture, where the system fails to properly authenticate and validate user requests before executing privileged operations. The vulnerability can be exploited by simply crafting a malicious HTTP request with the appropriate parameters, making it particularly dangerous as it requires minimal technical expertise to exploit and can be automated through various attack frameworks. The use of the big5 encoding in the request parameters suggests that the appliance may be configured for specific regional character sets, but this does not mitigate the underlying CSRF vulnerability. This vulnerability demonstrates a critical failure in the principle of least privilege and proper input validation, as the system does not verify the legitimacy of requests attempting to modify security policies. The attack scenario involves an attacker constructing a malicious request that, when executed by an authenticated user, would add the malicious email address to the whitelist, effectively allowing the attacker to bypass email security controls and potentially gain access to sensitive information or conduct further attacks through the compromised appliance. The vulnerability represents a significant risk to organizations relying on MailSherlock MSR35 and MSR45 appliances for email security, as it allows attackers to compromise the appliance's security controls and potentially gain access to the broader network through compromised email systems. The impact extends beyond immediate email security breaches to potential network infiltration, data exfiltration, and the establishment of persistent threat presence within the organization's email infrastructure. Organizations should immediately implement mitigations including input validation, CSRF token implementation, and proper access controls to prevent unauthorized modifications to security policies through web interfaces. The vulnerability highlights the importance of proper security testing and validation of web applications, particularly those handling critical security functions, and demonstrates the necessity of implementing comprehensive security controls beyond basic authentication mechanisms.