CVE-2018-6289 in Secure Mail Gateway
Summary
by MITRE
Configuration file injection leading to Code Execution as Root in Kaspersky Secure Mail Gateway version 1.1.
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Analysis
by VulDB Data Team • 01/02/2020
The CVE-2018-6289 vulnerability represents a critical configuration file injection flaw that affects Kaspersky Secure Mail Gateway version 1.1, fundamentally compromising system integrity and security posture. This vulnerability stems from improper input validation within the mail gateway's configuration management subsystem, allowing malicious actors to inject arbitrary configuration directives that ultimately execute with root privileges. The flaw exists in the way the system processes user-supplied data during configuration file updates, creating a path for remote code execution that bypasses standard security controls. The vulnerability is particularly concerning given the privileged execution context, as successful exploitation grants attackers complete control over the mail gateway infrastructure with the highest possible system privileges.
The technical implementation of this vulnerability follows a classic file injection pattern where attacker-controlled input is directly incorporated into system configuration files without adequate sanitization or validation. When the mail gateway processes configuration updates, it fails to properly validate or escape special characters and command sequences that could alter the intended behavior of the system. This flaw aligns with CWE-94, which describes "Improper Control of Generation of Code" and specifically relates to situations where external input is used to generate executable code or configuration data. The vulnerability operates at the application level within the Kaspersky Secure Mail Gateway's administrative interface, where configuration changes are processed and applied to the underlying system. Attackers can leverage this weakness by crafting malicious configuration data that when processed by the vulnerable system, executes arbitrary commands with root privileges.
The operational impact of CVE-2018-6289 extends far beyond simple privilege escalation, as it fundamentally undermines the security architecture of email protection services. Once exploited, attackers can manipulate email routing rules, access sensitive mail data, modify security policies, and potentially use the compromised gateway as a pivot point to attack other systems within the network. The vulnerability's ability to execute code as root means that attackers can install persistent backdoors, modify system binaries, and establish covert communication channels that would be extremely difficult to detect. This represents a significant risk to organizations relying on Kaspersky Secure Mail Gateway for email security, as the compromise of this system can lead to complete email infrastructure takeover. The attack surface is particularly broad given that email gateways often serve as central points of access for enterprise communications, making successful exploitation potentially devastating for business continuity and data protection.
Mitigation strategies for CVE-2018-6289 require immediate attention through patch management and operational security enhancements. Organizations must prioritize applying the vendor-provided security patches that address the configuration file injection vulnerability and implement network segmentation to limit access to the mail gateway. The remediation process should include thorough configuration reviews to ensure that input validation mechanisms are properly implemented and that the system operates with the principle of least privilege. Security monitoring should be enhanced to detect anomalous configuration changes and unusual command execution patterns that might indicate exploitation attempts. Additionally, implementing web application firewalls and input validation controls can provide additional layers of protection against similar vulnerabilities. This vulnerability highlights the importance of proper input sanitization and secure coding practices, aligning with ATT&CK technique T1059.001 for Command and Scripting Interpreter and T1068 for Exploitation for Privilege Escalation, which emphasize the need for robust defenses against code injection attacks. Organizations should also consider implementing automated vulnerability scanning and regular security assessments to identify and remediate similar weaknesses in their email infrastructure and other critical systems.