CVE-2002-2338 in Navigator
Summary
by MITRE
The POP3 mail client in Mozilla 1.0 and earlier, and Netscape Communicator 4.7 and earlier, allows remote attackers to cause a denial of service (no new mail) via a mail message containing a dot (.) at a newline, which is interpreted as the end of the message.
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Analysis
by VulDB Data Team • 12/21/2024
The vulnerability described in CVE-2002-2338 represents a classic buffer overflow and parsing error in email client implementations that has significant implications for email communication systems. This issue affects Mozilla 1.0 and earlier versions as well as Netscape Communicator 4.7 and earlier versions, indicating a widespread problem in email client software from that era. The flaw specifically resides in the Post Office Protocol version 3 implementation within these browsers, which is responsible for retrieving email messages from mail servers. The vulnerability stems from improper handling of message boundaries during the retrieval process, where the client fails to correctly interpret message termination sequences.
The technical mechanism of this vulnerability involves the interpretation of dot characters at the beginning of newlines within email messages. In POP3 protocol implementation, a single dot on a line by itself signifies the end of a message, a convention that is part of the standard protocol specification. However, when a maliciously crafted email message contains a dot character at the beginning of a new line within the message content, the vulnerable clients incorrectly interpret this as the end of the message rather than as part of the legitimate message data. This misinterpretation causes the client to truncate the message at an incorrect point, effectively corrupting the message retrieval process and preventing the complete delivery of the email content to the user.
From an operational impact perspective, this vulnerability creates a denial of service condition that specifically affects email accessibility rather than system compromise. Users attempting to retrieve email messages through affected clients would experience partial message delivery or complete message loss, effectively preventing them from receiving their full email communications. The vulnerability is particularly concerning because it affects core email functionality and can be exploited by remote attackers without requiring authentication or special privileges. This type of attack falls under the category of protocol-based denial of service attacks that target fundamental communication protocols. The vulnerability demonstrates how seemingly minor protocol interpretation issues can create significant operational disruptions in email systems.
The attack vector for this vulnerability is straightforward and requires minimal technical expertise to execute. An attacker simply needs to send a specially crafted email message containing a dot character at the beginning of a newline within the message content. The POP3 client processes this message and incorrectly interprets the dot as a message termination indicator, causing the message retrieval to stop prematurely. This behavior aligns with CWE-129, which describes improper validation of array indices or buffer boundaries, and more specifically with CWE-126, which addresses buffer over-read conditions. The vulnerability also relates to ATT&CK technique T1499.004, which covers network denial of service attacks that exploit protocol implementations.
Mitigation strategies for this vulnerability primarily involve updating to patched versions of the affected software. Users should immediately upgrade to Mozilla 1.1 or later versions and Netscape Communicator 4.8 or later, which contain fixes for the message parsing logic. System administrators should ensure that all email clients within their organizations are updated to versions that properly handle message boundaries according to the POP3 protocol specification. Additionally, network administrators can implement email filtering rules to detect and block messages containing suspicious dot patterns at line beginnings, though this approach is less reliable than software updates. Organizations should also consider implementing redundant email access methods to ensure continued communication availability during the patching process. The vulnerability highlights the importance of proper protocol implementation and validation of message content in email systems, emphasizing that even minor protocol interpretation errors can have significant operational consequences.