CVE-2008-5429 in Incredimail
Summary
by MITRE
Incredimail build 5853710 does not properly handle (1) multipart/mixed e-mail messages with many MIME parts and possibly (2) e-mail messages with many "Content-type: message/rfc822;" headers, which allows remote attackers to cause a denial of service (stack consumption or other resource consumption) via a large e-mail message, a related issue to CVE-2006-1173.
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Analysis
by VulDB Data Team • 10/21/2018
The vulnerability identified as CVE-2008-5429 affects Incredimail version 5853710 and represents a significant denial of service weakness in email client processing. This flaw specifically manifests when the application encounters email messages containing excessive MIME parts within multipart/mixed content structures or an excessive number of message/rfc822 content-type headers. The vulnerability operates as a resource exhaustion attack vector that can consume system memory and stack space, ultimately leading to application instability or complete crash. The issue is particularly concerning because it allows remote attackers to exploit this weakness without requiring authentication or privileged access, making it a serious security concern for email client users.
The technical implementation of this vulnerability stems from inadequate input validation and processing logic within Incredimail's email parsing engine. When the application receives email messages with numerous MIME parts or excessive rfc822 headers, the parsing routine fails to properly limit or manage resource allocation during message processing. This leads to uncontrolled stack consumption as the application attempts to recursively process nested message structures or maintain excessive data structures in memory. The flaw operates at the application layer and specifically targets the email message parsing functionality, where the client attempts to handle complex multipart messages that exceed normal processing boundaries. This behavior aligns with CWE-400, which classifies improper resource management as a fundamental weakness in software design that can lead to denial of service conditions.
The operational impact of this vulnerability extends beyond simple application crashes to encompass broader system stability concerns and potential service disruption. Attackers can craft specially formatted email messages that trigger the resource exhaustion condition, causing the email client to consume excessive system resources or crash entirely. This denial of service condition affects end users who rely on Incredimail for their email communication, potentially disrupting business operations or personal productivity. The vulnerability is particularly dangerous because it can be exploited through legitimate email reception, meaning users do not need to perform any malicious actions beyond receiving an email message. The related nature of this issue to CVE-2006-1173 indicates a persistent pattern in Incredimail's email processing implementation where similar resource management flaws exist, suggesting a systemic weakness in the application's architecture.
From an attack perspective, this vulnerability maps to several ATT&CK techniques including TA0040 (Resource Exhaustion) and TA0001 (Initial Access) where attackers can establish a foothold through email delivery mechanisms. The attack chain typically involves sending a specially crafted email message to a target user, which then triggers the vulnerable parsing logic upon message display or processing. Organizations using Incredimail should consider this vulnerability as part of their email security posture, particularly in environments where email-based attacks are a concern. The vulnerability also demonstrates the importance of input validation and resource management in email clients, as similar issues can be found in other email processing applications. Effective mitigation requires both immediate patching of the vulnerable Incredimail version and implementation of email filtering mechanisms that can detect and quarantine suspicious email content before it reaches end users. The vulnerability serves as a reminder of the critical importance of robust resource management in email processing applications and the potential for seemingly benign email content to cause significant system instability.
This vulnerability represents a classic example of how improper handling of structured data can lead to security issues in client applications. The lack of proper bounds checking and resource allocation management in the email parsing logic creates an exploitable condition where legitimate email processing becomes a vector for resource exhaustion attacks. The impact is particularly severe because it affects the core functionality of an email client, potentially rendering the application unusable and forcing users to restart their email clients or entire systems to recover normal operation. Organizations should consider implementing email gateway filtering to prevent such malicious messages from reaching vulnerable client applications, while also ensuring that all email clients are updated to versions that properly address these resource management issues. The vulnerability highlights the need for comprehensive security testing of email processing functionality, particularly around handling of complex or malformed email structures that could be exploited by attackers.