CVE-2004-1316 in Mozilla
Summary
by MITRE
Heap-based buffer overflow in MSG_UnEscapeSearchUrl in nsNNTPProtocol.cpp for Mozilla 1.7.3 and earlier allows remote attackers to cause a denial of service (application crash) via an NNTP URL (news:) with a trailing \ (backslash) character, which prevents a string from being NULL terminated.
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Analysis
by VulDB Data Team • 07/06/2025
The vulnerability identified as CVE-2004-1316 represents a critical heap-based buffer overflow in the Mozilla 1.7.3 browser and earlier versions that specifically affects the MSG_UnEscapeSearchUrl function within the nsNNTPProtocol.cpp source file. This flaw exists in the Network News Transfer Protocol implementation responsible for handling news: URLs that are used to access Usenet newsgroups through web browsers. The vulnerability manifests when processing NNTP URLs containing a trailing backslash character, creating a condition where the string handling mechanism fails to properly null-terminate the processed data, leading to memory corruption in the heap allocation area.
The technical exploitation of this vulnerability occurs through the manipulation of URL parsing logic where the trailing backslash character causes the buffer overflow condition during the unescaping process of news protocol URLs. When the browser encounters a news: URL with a backslash at the end, the MSG_UnEscapeSearchUrl function attempts to process this malformed input without proper boundary checking. The insufficient input validation allows an attacker to overwrite adjacent heap memory locations, potentially causing the application to crash or behave unpredictably. This type of heap overflow is particularly dangerous because it can be leveraged for more sophisticated attacks beyond simple denial of service, as it represents a fundamental memory corruption vulnerability that can be exploited to execute arbitrary code.
The operational impact of this vulnerability extends beyond simple application instability, as it provides remote attackers with a reliable method to cause persistent denial of service against affected systems. Users browsing the web or accessing news groups through vulnerable Mozilla installations could be targeted by malicious actors who craft specially formatted news: URLs to trigger the buffer overflow condition. The vulnerability affects all versions of Mozilla browser up to and including 1.7.3, making it a widespread concern for organizations using these older browser versions. The exploitation mechanism is straightforward and does not require special privileges or complex attack vectors, making it particularly dangerous in environments where users may inadvertently encounter malicious content.
This vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite heap memory, and corresponds to ATT&CK technique T1203, which involves exploiting input validation flaws to cause application instability. The flaw demonstrates poor input sanitization practices in protocol handling code and represents a classic example of how string manipulation functions can lead to memory corruption when proper null termination checks are omitted. Organizations should immediately implement mitigations by upgrading to Mozilla 1.7.4 or later versions where this vulnerability has been patched, as well as implementing network-based restrictions on news: URL handling and user education to avoid clicking on suspicious links. Additionally, deploying intrusion detection systems that can identify attempts to exploit this specific buffer overflow pattern provides an additional layer of defense against potential exploitation attempts.