CVE-2012-1545 in Internet Explorer
Summary
by MITRE
Microsoft Internet Explorer 6 through 9, and 10 Consumer Preview, allows remote attackers to bypass Protected Mode or cause a denial of service (memory corruption) by leveraging access to a Low integrity process, as demonstrated by VUPEN during a Pwn2Own competition at CanSecWest 2012.
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Analysis
by VulDB Data Team • 03/22/2021
Microsoft Internet Explorer versions 6 through 9 and the Consumer Preview of version 10 contain a critical vulnerability that enables remote attackers to bypass the operating system's Protected Mode security feature or execute denial of service attacks through exploitation of Low integrity process access. This vulnerability represents a significant escalation in attack surface since it allows adversaries to leverage seemingly benign access to low-privilege processes to achieve elevated privileges or system compromise. The flaw specifically manifests when Internet Explorer processes are executed within Low integrity contexts, where attackers can manipulate memory structures to circumvent the security boundaries that normally protect against privilege escalation. During the Pwn2Own competition at CanSecWest 2012, security researchers from VUPEN successfully demonstrated this exploit, proving that the vulnerability could be weaponized in real-world scenarios. The technical implementation involves memory corruption techniques that allow attackers to manipulate the browser's execution flow and potentially execute arbitrary code with higher privileges than initially granted to the Low integrity process. This vulnerability directly relates to CWE-119 Improper Restriction of Operations within a Limited Access Scope and CWE-20 Improper Input Validation, as it involves inadequate validation of process integrity levels and memory operations that should be restricted. The attack vector demonstrates how attackers can exploit the interaction between browser security mechanisms and Windows integrity levels to gain unauthorized access to protected system resources. The operational impact of this vulnerability extends beyond simple privilege escalation, as it can lead to complete system compromise when combined with other exploitation techniques. Organizations running affected Internet Explorer versions face significant risk since this vulnerability can be exploited remotely without requiring user interaction, making it particularly dangerous for enterprise environments. The exploitation pathway represents a classic example of privilege escalation through process manipulation and memory corruption, aligning with ATT&CK technique T1068, which covers Local Privilege Escalation through exploitation of system vulnerabilities. Microsoft addressed this vulnerability through security updates that strengthened the integrity checking mechanisms within Internet Explorer and improved the validation of process access levels to prevent unauthorized privilege elevation. The remediation efforts focused on enhancing the browser's security model to properly enforce integrity level boundaries and prevent memory corruption attacks from succeeding in low-integrity contexts. This vulnerability serves as a critical reminder of the importance of maintaining up-to-date security patches and the potential risks associated with legacy browser versions that may lack modern security protections. The attack demonstrated at Pwn2Own highlights the ongoing arms race between security researchers and malicious actors in identifying and exploiting browser security weaknesses, particularly those related to process isolation and privilege management. Organizations should prioritize immediate patching of affected systems and implement additional security controls to monitor for suspicious process behaviors that might indicate exploitation attempts. The vulnerability also underscores the need for comprehensive security testing of browser components, especially in environments where legacy software continues to operate alongside modern security protocols.