CVE-2022-26925

CVE-2022-26925 is a spoofing vulnerability in the Windows Local Security Authority (LSA) that lets an unauthenticated network attacker make a spoofed call to LSA on a remote Windows host. It is triggered over the network with no user interaction, typically by coercing a Windows system—most critically a domain controller—into authenticating via NTLM to an attacker-controlled machine, in the manner of the PetitPotam forced-authentication attacks referenced in CISA's catalog update. By spoofing the client when LSA processes that authentication, the attacker undermines NTLM's authentication guarantees and, when chained with relay techniques, can authenticate to a domain controller with elevated privileges, which is reflected in the CVSS high-integrity impact. Any organization running affected Windows clients or Windows Server versions is exposed, with domain controllers the highest-value targets. The flaw was exploited as a zero-day before Microsoft's June 2022 Patch Tuesday fixes and is now listed in CISA's Known Exploited Vulnerabilities catalog, with CISA ordering federal agencies to patch.

What to do: Apply Microsoft's June 2022 Patch Tuesday updates (per CISA's guidance for the June Microsoft patch, https://www.cisa.gov/guidance-applying-june-microsoft-patch) across all affected Windows versions, prioritizing domain controllers; systems that cannot yet patch should be protected with NTLM-related mitigations (e.g., enforced SMB signing, LDAP signing/channel binding, and restricting or auditing NTLM use) per CISA/Microsoft remediation guidance. Check whether domain controllers are internet-exposed or reachable from untrusted networks, and hunt for signs of forced-authentication/relay activity. Note that a related PetitPotam KEV entry was superseded, so ensure this newer LSA fix—not just the older PetitPotam patch—is deployed.