Zooming in on Zero-click Exploits
Summary: Google Project Zero researcher Natalie Silvanovich reported two Zoom vulnerabilities, a buffer overflow affecting both Zoom clients and MMR servers and an info leak useful only to attackers on MMR servers, both fixed on November 24, 2021. The buffer overflow, CVE-2021-34423, stems from deserialization code in libssb_sdk.so that allocates a string buffer using one length read from the message and then reads a second length to fill it, allowing an overwrite of up to 0x1FFF bytes.
Why it matters: The zero-click surface Silvanovich examined is reachable by anyone a target has accepted as a Zoom Contact, and the same vulnerable class was present on the MMR server used during Zoom Webinars, where large groups of unknown attendees can join.
Read the original at Google Project Zero ↗
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