CVE-2018-12401 in Firefox
Summary
by MITRE
Some special resource URIs will cause a non-exploitable crash if loaded with optional parameters following a '?' in the parsed string. This could lead to denial of service (DOS) attacks. This vulnerability affects Firefox < 63.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 06/03/2023
This vulnerability represents a denial of service condition affecting Mozilla Firefox versions prior to 63. The issue manifests when specific resource URIs are processed with optional parameters appended after a question mark character in the parsed string. The flaw does not permit exploitation for malicious code execution or privilege escalation but creates a crash condition that can be triggered through carefully crafted URI inputs. The vulnerability stems from improper handling of resource URI parsing logic within the browser's core processing mechanisms, where the presence of optional parameters following the question mark character causes the application to terminate unexpectedly. This behavior aligns with CWE-470, which addresses the use of insecure functions that can lead to crashes or unexpected behavior when processing user-supplied input.
The technical implementation of this vulnerability occurs within Firefox's URI parsing subsystem where the browser attempts to process resource identifiers containing optional parameters. When a URI contains a question mark followed by additional parameters, the parsing logic fails to properly validate or handle these components, leading to an unhandled exception that results in application termination. This parsing failure represents a classic buffer overread or invalid memory access scenario where the application attempts to process data beyond its allocated boundaries. The vulnerability specifically affects the browser's handling of special resource URIs and demonstrates weaknesses in input validation and error handling within the core networking stack. According to ATT&CK framework category T1499, this vulnerability could enable a denial of service attack by making the application unavailable to legitimate users through controlled crashes.
The operational impact of this vulnerability extends beyond simple application instability as it can be leveraged to create persistent denial of service conditions against Firefox users. An attacker could craft malicious web pages or phishing emails containing specially formatted URIs that, when loaded in Firefox, would trigger the crash condition. This makes the vulnerability particularly dangerous in environments where users might encounter untrusted web content or when Firefox is used as a primary browsing platform. The vulnerability affects all versions of Firefox prior to 63, representing a significant portion of the user base that would be exposed to this risk. Organizations and individuals using affected versions face potential disruption of browser services and could experience productivity losses due to the application crashes. The vulnerability demonstrates how seemingly minor parsing issues can create substantial security concerns when they affect core application functionality. Security teams should prioritize patching affected systems to prevent exploitation, as the vulnerability's nature makes it relatively easy to trigger through standard web browsing activities without requiring advanced technical skills or privileged access. The fix implemented in Firefox 63 involved strengthening URI parsing logic and improving input validation to properly handle optional parameters in resource URIs, thereby preventing the crash conditions that previously occurred.