CVE-2019-9818 in Firefox
Summary
by MITRE
A race condition is present in the crash generation server used to generate data for the crash reporter. This issue can lead to a use-after-free in the main process, resulting in a potentially exploitable crash and a sandbox escape. *Note: this vulnerability only affects Windows. Other operating systems are unaffected.*. This vulnerability affects Thunderbird < 60.7, Firefox < 67, and Firefox ESR < 60.7.
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Analysis
by VulDB Data Team • 06/05/2024
The vulnerability described in CVE-2019-9818 represents a critical race condition within Firefox and Thunderbird's crash reporting infrastructure specifically on Windows operating systems. This flaw exists in the crash generation server component responsible for creating crash data reports, creating a window of opportunity where memory management operations can be exploited by malicious actors. The race condition occurs during the interaction between the crash reporting process and the main application process, allowing for improper memory handling that can be leveraged for arbitrary code execution. The vulnerability is particularly concerning because it can lead to a use-after-free condition in the main process, which represents a fundamental memory safety violation that can be exploited to gain control over the application's execution flow.
The technical implementation of this vulnerability stems from improper synchronization mechanisms within the crash reporting subsystem that handles memory allocation and deallocation during crash processing. When the crash generation server attempts to process crash data while the main process is simultaneously managing memory resources, a timing window emerges where freed memory can be accessed and potentially reused before proper cleanup occurs. This race condition creates a scenario where an attacker can manipulate the timing of memory operations to cause the main process to execute code from previously freed memory locations, effectively enabling arbitrary code execution. The flaw specifically impacts Windows systems due to differences in memory management and process isolation mechanisms between operating systems, making it a platform-specific vulnerability that requires targeted exploitation techniques.
The operational impact of CVE-2019-9818 extends beyond simple privilege escalation to include potential sandbox escape capabilities that can bypass security boundaries within the browser environment. This vulnerability allows attackers to move from a restricted sandboxed environment to full system access, representing a severe compromise of the browser's security model. The use-after-free condition can be exploited through carefully crafted crash scenarios or by manipulating the crash reporting process itself, potentially enabling attackers to execute malicious code with the privileges of the affected application. This capability directly violates the principle of least privilege and can result in complete system compromise, data theft, or persistent backdoor installation. The vulnerability affects multiple versions of Firefox and Thunderbird, creating a wide attack surface across various software deployments in enterprise and consumer environments.
Mitigation strategies for CVE-2019-9818 primarily focus on immediate software updates to patched versions that address the underlying race condition in the crash reporting subsystem. Organizations should prioritize updating Firefox to version 67 or later, Thunderbird to version 60.7 or later, and Firefox ESR to version 60.7 or later to eliminate the vulnerability. System administrators should implement network monitoring to detect unusual crash reporting activity that might indicate exploitation attempts, as the vulnerability requires specific timing conditions to be successful. Additionally, implementing application whitelisting and strict process isolation can help limit the impact if exploitation occurs, while disabling crash reporting features entirely can prevent the vulnerability from being exploited. This vulnerability aligns with CWE-362, which describes race conditions in concurrent programming, and maps to ATT&CK technique T1059.001 for command and scripting interpreter execution, as successful exploitation can lead to code execution within the target environment. 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.