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Proof-of-concept (PoC) exploit code has been released for a Windows flaw, which could allow attackers to infiltrate enterprises by gaining administrative privileges, giving them access to companies’ Active Directory domain controllers (DCs). The vulnerability, dubbed “Zerologon,” is a privilege-escalation glitch (CVE-2020-1472) with a CVSS score of 10 out of 10, making it critical in severity. The flaw was addressed in Microsoft’s August 2020 security updates. However, this week at least four public PoC exploits for the flaw were released on Github, and on Friday, researchers with Secura (who discovered the flaw) published technical details of the vulnerability. “This attack has a huge impact: It basically allows any attacker on the local network (such as a malicious insider or someone who simply plugged in a device to an on-premise network port) to completely compromise the Windows domain,” said researchers with Secura, in a Friday whitepaper. “The attack is completely unauthenticated: The attacker does not need any user credentials.” Click to register. The flaw stems from the Netlogon Remote Protocol, available on Windows domain controllers, which is used for various tasks related to user and machine authentication. Specifically, the issue exists in the usage of AES-CFB8 encryption for Netlogon sessions. The AES-CFB8 standard requires that each “byte” of plaintext have a randomized initialization vector (IV), blocking attackers from guessing passwords. However,…

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