CVE-2008-0859 in MailServer
Summary
by MITRE
Unspecified vulnerability in Kerio MailServer before 6.5.0 allows remote attackers to cause a denial of service (crash) via unspecified vectors related to decoding of uuencoded input, which triggers memory corruption.
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Analysis
by VulDB Data Team • 08/05/2019
The vulnerability identified as CVE-2008-0859 represents a critical security flaw within Kerio MailServer versions prior to 6.5.0 that enables remote attackers to execute denial of service attacks through manipulation of uuencoded input data. This issue falls under the broader category of memory corruption vulnerabilities that can lead to system instability and service disruption. The vulnerability specifically targets the mail server's handling of uuencoded data streams during the decoding process, creating a pathway for malicious actors to exploit the software's input validation mechanisms.
The technical implementation of this vulnerability stems from inadequate input sanitization and memory management within the Kerio MailServer's uuencoding decoder component. When the system processes maliciously crafted uuencoded data, the decoding routine fails to properly validate or handle malformed input sequences, leading to memory corruption conditions that ultimately result in application crashes. This memory corruption typically occurs through buffer overflows or improper memory deallocation patterns that are common in legacy software implementations where input validation was not sufficiently robust. The vulnerability's classification as unspecified vectors indicates that the exact attack pathways may vary, but all involve the manipulation of uuencoded data streams that traverse the mail server's processing pipeline.
From an operational perspective, this vulnerability poses significant risks to organizations relying on Kerio MailServer for email services, as it allows remote attackers to disrupt email availability without requiring authentication or privileged access. The denial of service impact can result in complete email service outages, affecting business communications and potentially causing financial losses due to downtime. Network administrators may observe sudden service interruptions, application crashes, and potential system instability that could affect other services running on the same infrastructure. The remote nature of the attack means that adversaries can exploit this vulnerability from anywhere on the internet without needing physical access to the mail server infrastructure.
Organizations should implement immediate mitigations including upgrading to Kerio MailServer version 6.5.0 or later, which contains the necessary patches to address the memory corruption issues in the uuencoding decoder. Network segmentation and firewall rules can be implemented to limit exposure of the mail server to untrusted networks, while monitoring systems should be deployed to detect unusual traffic patterns or service disruptions that may indicate exploitation attempts. The vulnerability aligns with CWE-125, which describes out-of-bounds read conditions, and CWE-787, which covers out-of-bounds write conditions, both of which are common manifestations of memory corruption vulnerabilities. From an ATT&CK framework perspective, this vulnerability maps to T1499.004 for endpoint denial of service and T1595.001 for reconnaissance through information gathering, as attackers may probe for vulnerable systems before launching exploitation attempts. The security community should also consider implementing intrusion detection systems capable of identifying suspicious uuencoded data patterns and establishing incident response procedures for handling potential exploitation attempts.