CVE-2021-1782, an iOS in-the-wild vulnerability in vouchers
Summary: Google Project Zero's Ian Beer published an analysis of CVE-2021-1782, an XNU vouchers subsystem vulnerability fixed in iOS 14.4 on January 26th 2021, which Apple's release notes later updated on May 28th 2021 to say may have been actively exploited in the wild. The writeup traces the bug through the voucher codebase, where vouchers are reference-counted tables of keys and values deduplicated in the global ivht_bucket hash table, and only four of the eight inline table entries - IMPORTANCE, BANK, PTHPRIORITY and USER_DATA - are actually supported.
Bottom line: This was an in-the-wild iOS exploit against a kernel subsystem obscure enough that the writeup serves as its missing documentation - a reminder that the components your security team has never read are still reachable by attackers who have.
Read the original at Google Project Zero ↗
- Topics
- Zero-Days & Exploits
- Mentions
- CVE-2021-1782
- Related
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