CVE-2012-1527 in Windows
Summary
by MITRE
Integer underflow in Windows Shell in Microsoft Windows XP SP2 and SP3, Windows Server 2003 SP2, Windows Vista SP2, Windows Server 2008 SP2, R2, and R2 SP1, Windows 7 Gold and SP1, Windows 8, and Windows Server 2012 allows local users to gain privileges via a crafted briefcase, aka "Windows Briefcase Integer Underflow Vulnerability."
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Analysis
by VulDB Data Team • 04/19/2021
The CVE-2012-1527 vulnerability represents a critical integer underflow condition within the Windows Shell component of multiple Microsoft operating systems including Windows XP SP2 and SP3, Windows Server 2003 SP2, Windows Vista SP2, Windows Server 2008 SP2 and R2, Windows 7 Gold and SP1, Windows 8, and Windows Server 2012. This flaw specifically manifests in the Windows Briefcase functionality, which is designed to facilitate file compression and archiving operations. The vulnerability stems from improper input validation within the shell's handling of briefcase operations, creating a scenario where integer values can wrap around to negative numbers when they exceed their maximum positive limits. This particular issue aligns with CWE-191, which classifies integer underflow conditions, and falls under the broader category of memory safety vulnerabilities that can lead to privilege escalation. The vulnerability is particularly concerning because it operates within the Windows Shell, a core system component that handles numerous user interactions and system operations, making it an attractive target for exploitation.
The technical exploitation of this integer underflow occurs when a local attacker crafts a malicious briefcase file that triggers the vulnerable code path within the Windows Shell. When the system processes this malformed briefcase, the integer underflow causes memory corruption that can be leveraged to execute arbitrary code with elevated privileges. The attack vector requires local system access, meaning an attacker must already have user-level credentials to initiate the exploit. However, the successful exploitation results in privilege escalation, potentially allowing the attacker to gain SYSTEM-level access to the compromised system. This vulnerability demonstrates how seemingly benign file handling operations can contain critical security flaws that can be weaponized to bypass standard security controls. The integer underflow specifically affects the memory allocation and buffer management routines within the briefcase processing code, creating a predictable pattern of memory corruption that can be reliably exploited.
From an operational impact perspective, this vulnerability creates significant security risks for organizations running affected Windows versions, as it allows local attackers to escalate their privileges without requiring additional authentication mechanisms. The exploitation can lead to complete system compromise, enabling attackers to install malware, modify system files, access sensitive data, or establish persistent backdoors. The vulnerability affects a broad range of Microsoft operating systems, making it particularly dangerous in enterprise environments where multiple versions may coexist. Organizations that have not applied the relevant security updates are vulnerable to exploitation, as the integer underflow condition exists in the unpatched code. This vulnerability can be particularly problematic in environments where users have local access to systems, as it provides a straightforward path to privilege escalation. The impact extends beyond individual system compromise, as a successful exploitation could potentially allow attackers to move laterally within a network or establish persistent access to critical infrastructure.
Mitigation strategies for CVE-2012-1527 primarily involve applying the official Microsoft security patches released in May 2012 as part of the security update bulletin MS12-038. Organizations should prioritize patch deployment across all affected systems, particularly those running older Windows versions such as XP and Server 2003, which are no longer supported by Microsoft. Additional mitigations include implementing least privilege principles to limit local user access, disabling unnecessary file compression features, and monitoring for suspicious briefcase-related file operations. Security administrators should also consider implementing application whitelisting policies to restrict execution of potentially malicious briefcase files. The vulnerability's classification under the ATT&CK framework places it in the privilege escalation category, specifically targeting the 'Exploitation for Privilege Escalation' technique. Network segmentation and user access controls can help reduce the attack surface, while regular security assessments should verify that systems have been properly patched and remain secure against similar vulnerabilities. Organizations should also implement monitoring solutions that can detect anomalous briefcase processing activities that might indicate exploitation attempts.