CVE-2015-4487 in Firefox
Summary
by MITRE
The nsTSubstring::ReplacePrep function in Mozilla Firefox before 40.0, Firefox ESR 38.x before 38.2, and Firefox OS before 2.2 might allow remote attackers to cause a denial of service (memory corruption) or possibly have unspecified other impact via unknown vectors, related to an "overflow."
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Analysis
by VulDB Data Team • 10/22/2024
The vulnerability identified as CVE-2015-4487 resides within the nsTSubstring::ReplacePrep function of Mozilla Firefox versions prior to 40.0, Firefox ESR 38.x versions prior to 38.2, and Firefox OS versions prior to 2.2. This flaw represents a critical memory corruption issue that could be exploited by remote attackers to disrupt system operations or potentially achieve more severe consequences. The vulnerability stems from an overflow condition that occurs during string manipulation operations, specifically within the substring replacement functionality that forms part of Firefox's core text processing capabilities.
The technical nature of this vulnerability places it squarely within the realm of buffer overflow conditions that can lead to memory corruption. The nsTSubstring::ReplacePrep function handles the preparation of substring replacements, and when processing certain input parameters, it fails to properly validate the boundaries of memory allocations. This overflow condition creates opportunities for attackers to manipulate memory layouts in ways that can trigger system instability or potentially enable arbitrary code execution. The vulnerability's classification aligns with CWE-121, which describes stack-based buffer overflow conditions, and CWE-122, which addresses heap-based buffer overflows, though the specific implementation details suggest a more complex memory management issue.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as the memory corruption could potentially be leveraged for more sophisticated attacks. Remote attackers could craft malicious web content that, when processed by vulnerable Firefox installations, would trigger the overflow condition. This could result in browser crashes, application instability, or in more severe cases, arbitrary code execution within the context of the browser process. The vulnerability's presence across multiple Firefox variants including the ESR releases and Firefox OS demonstrates the widespread nature of the issue and its potential to affect numerous users simultaneously.
Mitigation strategies for CVE-2015-4487 primarily focus on immediate version upgrades to patched releases of Firefox and Firefox ESR. Users should ensure they are running Firefox 40.0 or later, Firefox ESR 38.2 or later, and Firefox OS 2.2 or later to eliminate exposure to this vulnerability. Additionally, security-conscious organizations should implement network-based protections such as web application firewalls that can detect and block malicious content targeting this specific vulnerability. The ATT&CK framework categorizes this type of vulnerability under T1059, which involves command and scripting interpreters, as attackers might use the memory corruption to execute malicious code. Organizations should also consider implementing memory protection mechanisms such as address space layout randomization and data execution prevention to reduce the effectiveness of potential exploitation attempts. Regular security assessments and vulnerability scanning should be conducted to ensure all Firefox installations remain up to date with the latest security patches, as this vulnerability represents a significant risk to user security and system integrity.