CVE-2018-12385 in Firefox
Summary
by MITRE
A potentially exploitable crash in TransportSecurityInfo used for SSL can be triggered by data stored in the local cache in the user profile directory. This issue is only exploitable in combination with another vulnerability allowing an attacker to write data into the local cache or from locally installed malware. This issue also triggers a non-exploitable startup crash for users switching between the Nightly and Release versions of Firefox if the same profile is used. This vulnerability affects Thunderbird < 60.2.1, Firefox ESR < 60.2.1, and Firefox < 62.0.2.
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Analysis
by VulDB Data Team • 05/30/2023
The vulnerability identified as CVE-2018-12385 represents a critical stability issue within Mozilla's Firefox and Thunderbird email clients that stems from improper handling of SSL/TLS transport security information stored in local user profile caches. This flaw manifests as a crash condition that can potentially be exploited when malicious data is written to the local cache, making it particularly dangerous in environments where user privileges may be compromised or where persistent malware exists on the system. The vulnerability specifically targets the TransportSecurityInfo component which manages security policies and certificates for secure communications, creating a potential vector for denial of service attacks that could disrupt normal user operations and potentially provide attackers with opportunities to escalate privileges or gain unauthorized access to secure communications channels.
The technical implementation of this vulnerability resides in how Firefox and Thunderbird process cached SSL security information during application startup and operation. When the application attempts to read and validate stored transport security data from the local user profile directory, malformed or malicious entries can cause the application to crash or behave unpredictably. This occurs because the parsing logic does not adequately validate or sanitize the cached data before processing it, allowing corrupted entries to trigger memory corruption or invalid memory access conditions. The issue is categorized under CWE-121, which deals with stack-based buffer overflow conditions, though the actual manifestation involves heap corruption and memory management failures that can be leveraged for more sophisticated attacks when combined with other exploitation techniques.
The operational impact of this vulnerability extends beyond simple application crashes, creating significant security implications for users who operate multiple versions of Firefox or Thunderbird using the same profile directory. When users switch between Nightly and Release versions of the browser, the cache data created by one version may contain structures that are incompatible with another, leading to startup crashes that prevent normal application operation. This scenario particularly affects power users and developers who maintain multiple browser versions for testing purposes, as it creates an operational disruption that can be exploited by attackers who understand the timing and conditions required for successful exploitation. The vulnerability also creates opportunities for attackers to craft specific cache entries that could trigger crashes or potentially execute arbitrary code, particularly when combined with other local privilege escalation vulnerabilities that allow for cache manipulation.
The exploitation of this vulnerability requires an attacker to first gain the ability to write data to the local cache directory, which typically requires either local system access or the presence of malware already installed on the target system. This prerequisite significantly reduces the attack surface but does not eliminate the threat entirely, as many users may unknowingly install malicious software that can manipulate the application cache. Security professionals should consider this vulnerability in the context of the ATT&CK framework under the T1059.001 technique for command and script interpreter, as it may be combined with other techniques to establish persistence or execute malicious code through cache manipulation. The vulnerability affects specific versions of Firefox and Thunderbird, including Thunderbird versions before 60.2.1, Firefox ESR versions before 60.2.1, and Firefox versions before 62.0.2, making version management and patch deployment critical for maintaining security posture.
Mitigation strategies for CVE-2018-12385 should focus on immediate patch deployment for all affected versions, as well as implementing strict access controls on user profile directories to prevent unauthorized cache modifications. Organizations should consider implementing automated patch management systems to ensure timely updates across all affected applications, particularly in enterprise environments where multiple browser versions may be in use. Additionally, security teams should monitor for signs of cache manipulation or unusual crash patterns that could indicate attempted exploitation, as well as implement application whitelisting policies that prevent execution of unsigned or untrusted code that might attempt to write malicious entries to the cache. Regular security audits of user profile directories and cache contents can help identify potential malicious modifications, while user education about the risks of downloading and executing untrusted software remains essential for reducing the likelihood of successful exploitation attempts.