CVE-2002-1255 in Outlook
Summary
by MITRE
Microsoft Outlook 2002 allows remote attackers to cause a denial of service (repeated failure) via an email message with a certain invalid header field that is accessed using POP3, IMAP, or WebDAV, aka "E-mail Header Processing Flaw Could Cause Outlook 2002 to Fail."
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Analysis
by VulDB Data Team • 05/20/2019
This vulnerability affects Microsoft Outlook 2002 and represents a classic denial of service flaw stemming from improper handling of malformed email headers during retrieval via POP3 IMAP or WebDAV protocols. The issue manifests when Outlook encounters an email message containing a specific type of invalid header field that triggers repeated processing failures. The vulnerability is categorized under CWE-129 as an input validation error where the application fails to properly validate header field data before processing. When Outlook attempts to parse the malformed header field, it enters a loop of repeated failure states rather than gracefully handling the invalid data, leading to sustained service disruption.
The technical implementation of this vulnerability exploits the email header parsing mechanism within Outlook 2002's email retrieval processes. During POP3 IMAP or WebDAV access operations, the application's header processing routine encounters the invalid field and fails to implement proper error recovery mechanisms. This failure mode creates a condition where Outlook repeatedly attempts to process the same malformed header, consuming system resources and preventing normal email processing operations. The flaw operates at the protocol level where Outlook's email client interacts with mail servers, making it particularly dangerous in enterprise environments where email availability is critical. The vulnerability aligns with ATT&CK technique T1499.004 which covers network denial of service attacks through malformed data processing.
The operational impact of this vulnerability extends beyond simple service disruption to create cascading effects within email infrastructure. When exploited, the repeated failure condition can overwhelm system resources and potentially impact other email processing activities within the same Outlook instance. Network administrators may observe degraded performance or complete email service outages for affected users. The vulnerability is particularly concerning in corporate environments where Outlook 2002 remains in use, as it can be leveraged by attackers to disrupt business communications without requiring privileged access or complex exploitation techniques. The flaw demonstrates poor defensive programming practices where error handling does not account for malformed input conditions that could cause indefinite processing loops.
Mitigation strategies for this vulnerability should focus on immediate patching of affected Outlook 2002 installations with Microsoft security updates. Organizations lacking immediate patch deployment capabilities should implement email filtering measures to identify and quarantine messages containing suspicious header field patterns. Network-level protections can include implementing email header validation rules at gateway appliances or mail server levels to prevent malformed headers from reaching client applications. The vulnerability highlights the importance of robust input validation and error recovery mechanisms in client applications, particularly those handling untrusted data from network sources. Security monitoring should include detection of repeated error patterns in email processing logs that may indicate exploitation attempts. Organizations should also consider migrating from legacy email clients to more modern versions that have addressed such fundamental parsing vulnerabilities through improved defensive programming practices and comprehensive error handling procedures.