CVE-2015-2548

Vulnerability

A use-after-free vulnerability exists in the Tablet Input Band component of Windows Shell on Microsoft Windows Vista Service Pack 2 and Windows 7 Service Pack 1 [1]. The flaw occurs when the system improperly handles objects in memory while processing specially crafted toolbar content. An attacker can trigger this condition by hosting a malicious website that, when visited by a user, causes the Tablet Input Band to reference freed memory [1].

Exploitation

To exploit this vulnerability, an attacker must convince a user to visit a crafted website (typically via email, instant message, or drive-by download). No additional privileges or user interaction beyond browsing are required. The attacker's site delivers a sequence of operations that triggers the use-after-free condition, leading to memory corruption that can be leveraged for code execution [1].

Impact

Successful exploitation grants the attacker arbitrary code execution in the security context of the currently logged-on user. The attacker can then install programs, view, change, or delete data, or create new accounts with full user rights. If the user has administrative privileges, the attacker can take complete control of the affected system [1].

Mitigation

Microsoft released security update MS15-109 (KB 3096443) on October 13, 2015, which addresses this vulnerability by correcting how the Tablet Input Band handles objects in memory [1]. All affected Windows versions (Vista SP2 and Windows 7 SP1) should apply the update immediately. No workarounds are documented; the only mitigation is to install the update or upgrade to a supported operating system [1].