CVE-2012-3565 in Web Browser
Summary
by MITRE
Opera before 12.00 Beta allows remote attackers to cause a denial of service (application crash) via crafted characters in domain names, as demonstrated by "IDNA2008 tests."
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Analysis
by VulDB Data Team • 01/22/2018
The vulnerability identified as CVE-2012-3565 affects Opera web browsers prior to version 12.00 Beta and represents a denial of service flaw stemming from improper handling of domain name characters. This issue specifically manifests when the browser encounters crafted characters within domain names during the Internationalizing Domain Names in Applications IDNA2008 validation process. The vulnerability exploits a weakness in how Opera processes internationalized domain names, which are domain names containing non-ascii characters that require special encoding for internet communication. When maliciously constructed domain names containing specific character sequences are processed by the affected browser, the application crashes and becomes unavailable to users.
The technical root cause of this vulnerability lies in the browser's insufficient input validation and error handling mechanisms within its IDNA2008 implementation. IDNA2008 is a standard for encoding internationalized domain names that allows for the use of non-ascii characters in domain names while maintaining compatibility with existing dns infrastructure. The flaw occurs during the normalization and validation phases of domain name processing where Opera fails to properly handle certain edge cases in character sequences that are valid according to IDNA2008 specifications but trigger internal buffer overflows or invalid memory access conditions. This type of vulnerability falls under CWE-129, which describes improper validation of array index values, and CWE-248, which covers exposure of an exception to the calling environment. The vulnerability is particularly concerning because it can be triggered through normal web browsing activities when users encounter maliciously crafted web pages or links containing the problematic domain names.
The operational impact of this vulnerability extends beyond simple application instability to potentially enable more sophisticated attack vectors. While the immediate effect is a denial of service causing browser crashes, attackers can leverage this weakness to disrupt user productivity and potentially gain access to other system resources through repeated exploitation attempts. The vulnerability affects users across all operating systems where the affected Opera versions are deployed, making it particularly dangerous in enterprise environments where multiple users might be simultaneously impacted. From an attacker perspective, this vulnerability aligns with ATT&CK technique T1499.004, which covers network denial of service attacks, and represents a form of application-level exploitation that can be used to create persistent availability issues. The vulnerability's exploitation requires minimal technical skill and can be automated through web-based attack vectors, making it attractive to threat actors seeking to disrupt services or create distractions.
Mitigation strategies for CVE-2012-3565 primarily focus on immediate software updates and system hardening measures. The most effective solution is upgrading to Opera version 12.00 Beta or later, which contains the necessary patches to properly handle IDNA2008 domain names without crashing. Organizations should implement automated patch management systems to ensure all affected browsers are updated promptly, as this vulnerability was disclosed in 2012 and represents a known weakness that has been addressed in subsequent releases. Network administrators can also implement additional protective measures such as dns filtering and web content filtering to prevent users from accessing malicious domains that contain the problematic character sequences. The vulnerability demonstrates the importance of proper input validation and error handling in security-critical applications, particularly those dealing with internationalization standards that require complex character processing. Security teams should also consider implementing monitoring solutions that can detect browser crash patterns or unusual application behavior that might indicate exploitation attempts, as these incidents could be part of broader attack campaigns targeting web browser vulnerabilities.