This issue is caused due to the Windows Print Spooler insufficiently restricting user permissions to access print spoolers, which could allow remote unauthenticated attackers to create a malicious file in a Windows system directory by sending a specially crafted print request to a shared printer. Systems are only vulnerable to remote attacks when a printer is shared and remotely available. By default, printers are not shared on Windows.
On Windows XP, the guest account is enabled by default, which allows anonymous users to access printer shares. On Windows Server 2003, Windows Vista, Windows Server 2008, Windows 7, and Windows Server 2008 R2, an attacker must be authenticated in order to exploit this vulnerability unless password-based sharing is disabled. If password-based sharing is disabled, attackers could exploit these systems without authentication.
This vulnerability is already being exploited by malware (e.g. Stuxnet)
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