CVE-2008-0858 in Visnetic Antivirus Plug-in For Mail Server
Summary
by MITRE
Buffer overflow in the Visnetic anti-virus plugin in Kerio MailServer before 6.5.0 might allow remote attackers to execute arbitrary code via unspecified vectors.
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Analysis
by VulDB Data Team • 08/05/2019
The vulnerability identified as CVE-2008-0858 represents a critical buffer overflow flaw within the Visnetic anti-virus plugin component of Kerio MailServer versions prior to 6.5.0. This issue resides in the email server's security infrastructure where the anti-virus scanning functionality fails to properly validate input data, creating an exploitable condition that could be leveraged by remote attackers to gain unauthorized system access. The vulnerability specifically affects the plugin architecture that integrates third-party anti-virus solutions into the mail server environment, making it particularly concerning given the widespread use of Kerio MailServer in enterprise environments. The buffer overflow occurs when the plugin processes incoming email attachments or content that exceeds predetermined memory boundaries, leading to potential memory corruption and arbitrary code execution.
The technical nature of this vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. In the context of Kerio MailServer, the Visnetic plugin likely receives untrusted data from email messages that contain maliciously crafted payloads designed to trigger the buffer overflow. This type of vulnerability typically arises from inadequate input validation mechanisms within the anti-virus scanning process, where the plugin does not properly sanitize or limit the size of data it processes before attempting to store it in allocated memory buffers. The flaw operates at the intersection of network security and application-level memory management, creating a pathway for remote code execution that bypasses normal authentication mechanisms.
The operational impact of this vulnerability extends beyond simple data compromise, as successful exploitation could enable attackers to establish persistent access to email servers and potentially escalate privileges within the network infrastructure. Enterprise email servers represent critical assets that handle sensitive corporate communications, making them attractive targets for cybercriminals seeking to gain unauthorized access to organizational data. The vulnerability's remote exploitability means that attackers do not require physical access or local credentials to leverage the flaw, significantly expanding the attack surface. Organizations using affected Kerio MailServer versions face potential risks including email content interception, unauthorized data exfiltration, and the possibility of using the compromised server as a launch point for further attacks against internal network resources. The attack vector typically involves sending specially crafted emails that trigger the vulnerable anti-virus plugin during the scanning process.
Mitigation strategies for CVE-2008-0858 primarily focus on immediate patch deployment and operational security enhancements. The most effective remediation involves upgrading to Kerio MailServer version 6.5.0 or later, which includes fixed implementations of the Visnetic plugin that properly validate input data and prevent buffer overflow conditions. Security administrators should also implement network-level controls such as email content filtering and sandboxing mechanisms to reduce the risk of exploitation even if patches are not immediately deployable. Additional protective measures include monitoring for unusual network activity patterns that might indicate exploitation attempts, implementing strict email attachment policies, and conducting regular vulnerability assessments of email server configurations. The ATT&CK framework categorizes this vulnerability under privilege escalation and execution techniques, specifically targeting server-side applications and network services where input validation failures create opportunities for attackers to gain unauthorized code execution privileges. Organizations should also consider implementing intrusion detection systems that can identify suspicious email traffic patterns associated with buffer overflow exploitation attempts.