A Token’s Tale

Summary: Project Zero's James Forshaw documented CVE-2015-0002, a flaw in the Windows 8.1 ahcache.sys driver where the AhcVerifyAdminContext function fails to verify that an impersonation token is at the privileged SecurityImpersonation level rather than the unprivileged SecurityIdentification level. He argued that a proof-of-concept is necessary because a report alone often fails to move a vendor from triage to patching, and a working PoC lets the vendor, customers, and the security industry confirm exploitability and test fixes.
Why it matters: The bug only becomes a security issue if a normal user can capture a Local System access token and impersonate it, which is why Forshaw judged that demonstrating token capture alone would prove nothing beyond documented behavior. For a security leader, the gap between a vendor acknowledging a report and actually shipping a patch is where the exposure lives.

Read the original at Google Project Zero ↗

Topics: Vulnerabilities & Patching
Mentions: CVE-2015-0002
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