Mitigating NTLM Relay Attacks by Default

Introduction In February 2024, we released an update to Exchange Server which contained a security improvement referenced by CVE-2024-21410 that enabled Extended Protection for Authentication EPA by default for new and existing installs of Exchange 2019. While we’re currently unaware of any activ...

Critical Exchange Server Flaw (CVE-2024-21410) Under Active Exploitation

Microsoft on Wednesday acknowledged that a newly disclosed critical security flaw in Exchange Server has been actively exploited in the wild, a day after it released fixes for the vulnerability as part of its Patch Tuesday updates. Tracked as CVE-2024-21410 CVSS score: 9.8, the issue has been...

Detecting and preventing privilege escalation attacks leveraging Kerberos relaying (KrbRelayUp)

On April 24, 2022, a privilege escalation hacking tool, KrbRelayUp, was publicly disclosed on GitHub by security researcher Mor Davidovich. KrbRelayUp is a wrapper that can streamline the use of some features in Rubeus, KrbRelay, SCMUACBypass, PowerMad/SharpMad, Whisker, and ADCSPwn tools in...

Microsoft Rushes Fix for ‘PetitPotam’ Attack PoC

Microsoft was quick to respond with a fix to an attack dubbed “PetitPotam” that could force remote Windows systems to reveal password hashes that could then be easily cracked. To thwart an attack, Microsoft recommends system administrators stop using the now deprecated Windows NT LAN Manager NTLM...

Mitigating NTLM Relay Attacks on Active Directory Certificate Services (AD CS)

Summary Microsoft is aware of PetitPotam which can potentially be used in an attack on Windows domain controllers or other Windows servers. PetitPotam is a classic NTLM Relay Attack, and such attacks have been previously documented by Microsoft along with numerous mitigation options to protect...

KLA12244 Microsoft Advisory for Active Directory Certificate Services

Microsoft is aware of PetitPotam which can potentially be used in an attack on Windows domain controllers or other Windows servers.To prevent NTLM Relay Attacks on networks with NTLM enabled, domain administrators must ensure that services that permit NTLM authentication make use of protections...

KLA12248 Microsoft Advisory (ESU) for Active Directory Certificate Services

Microsoft is aware of PetitPotam which can potentially be used in an attack on Windows domain controllers or other Microsoft Products Extended Security Update.To prevent NTLM Relay Attacks on networks with NTLM enabled, domain administrators must ensure that services that permit NTLM authenticati...

Security feature bypass

Microsoft Windows 7 SP1, Windows Server 2008 SP2 and R2 SP1, Windows 8.1 and Windows RT 8.1, Windows Server 2012 and R2, Windows 10 Gold, 1511, 1607, and 1703, and Windows Server 2016 allows an attacker to bypass Extended Protection for Authentication when Kerberos fails to prevent tampering with...