CVE-2015-4482 in Firefox
Summary
by MITRE
mar_read.c in the Updater in Mozilla Firefox before 40.0 and Firefox ESR 38.x before 38.2 allows local users to gain privileges or cause a denial of service (out-of-bounds write) via a crafted name of a Mozilla Archive (aka MAR) file.
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Analysis
by VulDB Data Team • 10/22/2024
The vulnerability identified as CVE-2015-4482 represents a critical out-of-bounds write flaw in the Mozilla Archive (MAR) file processing mechanism within Firefox's updater component. This issue affects Firefox versions prior to 40.0 and Firefox ESR 38.x versions before 38.2, where the mar_read.c file fails to properly validate the length of file names contained within MAR archives. The flaw occurs during the extraction process when the updater attempts to read and process archive file names without adequate bounds checking, creating a potential vector for privilege escalation or denial of service attacks. The vulnerability stems from improper input validation in the archive processing logic, which directly violates security principles outlined in CWE-129 and CWE-787, both of which address insufficient bounds checking and out-of-bounds writes in software systems.
The technical exploitation of this vulnerability involves crafting a malicious MAR file with an overly long or malformed file name that exceeds the allocated buffer space during processing. When Firefox's updater attempts to read this crafted archive, the insufficient bounds checking causes memory corruption that can result in arbitrary code execution with elevated privileges or system instability leading to denial of service conditions. This type of vulnerability falls under the ATT&CK technique T1059.007 for Command and Scripting Interpreter and T1068 for Exploitation for Privilege Escalation, as local attackers can leverage this flaw to execute malicious code with higher system privileges than normal user accounts. The vulnerability's impact is particularly severe because it operates within the update mechanism, which typically runs with elevated privileges to ensure proper system maintenance and security updates.
From an operational standpoint, this vulnerability presents significant risk to organizations deploying affected Firefox versions, as local attackers with minimal privileges can potentially escalate their access level to system administrator status. The denial of service component of this vulnerability means that even successful exploitation without privilege escalation can render the browser unusable and potentially impact system stability. The attack surface extends beyond individual user systems to enterprise environments where automated update processes might be compromised. Organizations should consider this vulnerability in their threat modeling exercises, particularly in environments where Firefox is used for sensitive operations and where local privilege escalation could provide access to critical systems or data. The vulnerability's classification as a local privilege escalation issue means that it does not require network connectivity for exploitation, making it particularly dangerous in environments where user access is not strictly controlled.
Mitigation strategies for CVE-2015-4482 should prioritize immediate patching of affected Firefox installations to versions 40.0 or later for standard releases and 38.2 for ESR releases. System administrators should implement monitoring for suspicious archive file processing activities and consider disabling automatic updates temporarily while applying patches. The vulnerability's nature suggests that organizations should review their update policies to ensure rapid deployment of security patches. Additionally, implementing network segmentation and access controls can limit the potential impact of successful exploitation attempts. Security teams should also consider deploying intrusion detection systems that can identify unusual file processing patterns or attempts to create malformed archive files. The remediation process should include thorough testing of patched versions to ensure that update functionality remains intact while addressing the underlying memory corruption issue. Organizations should also review their incident response procedures to prepare for potential exploitation attempts targeting this vulnerability, as the combination of privilege escalation and denial of service capabilities makes it particularly dangerous in enterprise environments.