CVE-2018-5693 in MagicSpam Extension
Summary
by MITRE
The LinuxMagic MagicSpam extension 2.0.13 for Plesk allows local users to discover mailbox names by reading /var/log/magicspam/mslog.
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Analysis
by VulDB Data Team • 12/23/2019
The vulnerability identified as CVE-2018-5693 resides within the LinuxMagic MagicSpam extension version 2.0.13 for Plesk, a widely used web hosting control panel solution. This security flaw represents a significant information disclosure weakness that affects the extension's logging mechanism and exposes sensitive mailbox information to local attackers. The vulnerability specifically manifests when the extension writes mailbox names to the /var/log/magicspam/mslog file, creating a potential attack vector for malicious actors with local system access. The MagicSpam extension is designed to provide spam filtering capabilities for email servers, but its implementation contains a critical oversight in how it handles sensitive data within its logging infrastructure.
The technical flaw stems from improper access control and logging practices within the MagicSpam extension's implementation. When the extension processes email traffic, it generates log entries that contain mailbox names in plaintext format within the /var/log/magicspam/mslog file. This logging mechanism does not adequately sanitize or restrict access to the information it stores, allowing any local user with read permissions to the log file to extract mailbox names. The vulnerability operates at the file system level where the extension fails to implement proper file permissions or data obfuscation techniques, creating a clear path for information disclosure attacks. This type of flaw aligns with CWE-200, which describes improper exposure of sensitive information, and represents a classic case of insufficient logging security controls.
The operational impact of CVE-2018-5693 extends beyond simple information disclosure, as it provides attackers with valuable reconnaissance data that can be leveraged for subsequent attacks. Local users who can access the log file gain knowledge of legitimate mailbox addresses on the system, which can be used for targeted phishing campaigns, credential stuffing attacks, or social engineering operations. The exposure of mailbox names creates a foundation for more sophisticated attacks such as account enumeration, where attackers can systematically identify valid user accounts and then attempt to compromise them through password guessing or brute force techniques. This vulnerability particularly affects environments where Plesk manages multiple customer mailboxes, as it provides attackers with a comprehensive list of potential targets. The impact is further amplified when considering that the MagicSpam extension typically operates within shared hosting environments where multiple users may have local access to the system.
Security practitioners should consider this vulnerability in the context of broader attack frameworks such as those defined by the MITRE ATT&CK methodology, where information gathering and reconnaissance activities are fundamental initial steps in attack chains. The vulnerability enables techniques categorized under T1087 (Account Discovery) and T1566 (Phishing) by providing attackers with valid mailbox information for crafting targeted attacks. Organizations using Plesk with the MagicSpam extension should immediately implement mitigations including restricting file permissions on the mslog file to prevent unauthorized local access, implementing proper log rotation with appropriate access controls, and considering the removal of sensitive information from log files. Additionally, system administrators should conduct comprehensive security audits to identify similar logging vulnerabilities across other extensions and applications within the Plesk environment. The recommended remediation approach involves applying the vendor-provided patch, which typically addresses the logging implementation by either removing the mailbox information from logs or implementing proper access controls on the log files themselves.