CVE-2001-0039 in IMail
Summary
by MITRE
IPSwitch IMail 6.0.5 allows remote attackers to cause a denial of service using the SMTP AUTH command by sending a base64-encoded user password whose length is between 80 and 136 bytes.
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Analysis
by VulDB Data Team • 05/18/2019
The vulnerability identified as CVE-2001-0039 represents a classic denial of service flaw affecting IPSwitch IMail 6.0.5 email server software. This issue specifically targets the SMTP authentication mechanism within the email server implementation, creating a condition where malicious actors can disrupt legitimate service operations. The vulnerability falls under the category of improper input validation, where the system fails to properly handle malformed or excessively long authentication parameters. According to CWE-20, this corresponds to improper input validation, which is a fundamental weakness that can lead to various security consequences including service disruption.
The technical exploitation of this vulnerability occurs through the manipulation of the SMTP AUTH command during the authentication process. Attackers craft base64-encoded user passwords with specific length constraints between 80 and 136 bytes to trigger the denial of service condition. This particular attack vector demonstrates how seemingly benign authentication parameters can be weaponized when the receiving system lacks proper boundary checking and input sanitization. The flaw likely stems from insufficient buffer management or string length validation within the IMail server's SMTP implementation, where the system does not adequately validate the length of encoded authentication data before processing it.
The operational impact of this vulnerability extends beyond simple service disruption, as it can affect email availability for legitimate users and potentially impact business operations that depend on email communication. Organizations utilizing IMail 6.0.5 may experience temporary or prolonged email service outages, affecting both incoming and outgoing email functionality. The attack requires minimal resources from the attacker while potentially causing significant disruption to the target organization's communication infrastructure. From an ATT&CK framework perspective, this vulnerability aligns with the T1499.004 technique related to network denial of service, and represents a specific implementation weakness that could be leveraged as part of broader attack campaigns targeting email infrastructure.
Mitigation strategies for CVE-2001-0039 should focus on immediate patching of the affected IMail server software to address the underlying input validation flaw. Organizations should implement network-level protections such as rate limiting and connection filtering to reduce the effectiveness of such attacks. Additionally, configuring the email server to enforce stricter authentication parameter validation and implementing monitoring systems to detect anomalous authentication patterns can provide defense-in-depth. The vulnerability also highlights the importance of regular security assessments and vulnerability management processes to identify and remediate similar flaws in legacy email server implementations. Given the age of this vulnerability, organizations should consider migrating to more modern email server solutions that have better security practices and ongoing support for security updates.