LM hash is a compromised protocol and has been replaced by NTLM hash. However, the in-memory copy of the contents of the SAM can be dumped using various techniques (including pwdump), making the password hashes available for offline brute-force attack. The SAM file cannot be moved or copied while Windows is running, since the Windows kernel obtains and keeps an exclusive filesystem lock on the SAM file, and will not release that lock until the operating system has shut down or a " Blue Screen of Death" exception has been thrown. In the case of online attacks, it is not possible to simply copy the SAM file to another location. In 2019, this time was reduced to roughly 2.5 hours by using more modern hardware. In 2012, it was demonstrated that every possible 8-character NTLM password hash permutation can be cracked in under 6 hours. As of Windows 10 version 1709, syskey was removed due to a combination of insecure security and misuse by bad actors to lock users out of systems. It can be enabled by running the syskey program. When SYSKEY is enabled, the on-disk copy of the SAM file is partially encrypted, so that the password hash values for all local accounts stored in the SAM are encrypted with a key (usually also referred to as the "SYSKEY"). In an attempt to improve the security of the SAM database against offline software cracking, Microsoft introduced the SYSKEY function in Windows NT 4.0.
This file can be found in %SystemRoot%/system32/config/SAM and is mounted on HKLM/SAM and SYSTEM privileges are required to view it. The user passwords are stored in a hashed format in a registry hive either as an LM hash or as an NTLM hash. SAM uses cryptographic measures to prevent unauthenticated users accessing the system. Beginning with Windows 2000 SP4, Active Directory authenticates remote users. It can be used to authenticate local and remote users. The Security Account Manager ( SAM) is a database file in Windows XP, Windows Vista, Windows 7, 8.1, 10 and 11 that stores users' passwords. ( Learn how and when to remove this template message)
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