Unpatched HiveNightmare/SeriousSAM Windows Zero-Day Allows Privileged File Access

An unpatched Windows security vulnerability could allow information disclosure and local privilege escalation (LPE), researchers have warned. The issue (CVE-2021-24084) has yet to get an official fix, making it a zero-day bug – but a micropatch has been rolled out as a stop-gap measure.

Security researcher Abdelhamid Naceri originally reported the vulnerability as an information-disclosure issue in October 2020, via Trend Micro’s Zero-Day Initiative (ZDI). Though Microsoft had told him it was planning a fix for last April, the patch has not yet been forthcoming.

Then, this month, Naceri discovered that CVE-2021-24084 could also be exploited for LPE, so that non-admin Windows users can read arbitrary files even if they do not have permissions to do so. In a proof-of-concept exploit, he demonstrated that it’s possible to copy files from a chosen location into a Cabinet (.CAB) archive that the user can then open and read.

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Source: ThreatPost