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Cyber Risks · Cisco Talos

Fuzzing µCOS protocol stacks, Part 2: Handling multiple requests per test case

Summary: Cisco Talos extended its µC/HTTP-server fuzzer to handle multiple requests per test case by adding a delimiter feature to the open-source libdesock library, which redirects socket reads to stdin via LD_PRELOAD. The multi-request fuzzer uncovered two additional vulnerabilities, both exploiting a flaw in the first request via a second request, and the affected codebase is shared across Silicon Labs Gecko Platform and Weston Embedded Cesium NET.

What you should know: One of the two bugs required four requests - two for heap grooming, a one-byte overwrite on the third, and an improper allocation on the fourth - meaning single-request testing would never have surfaced it, and the same code sits in products from two other vendors.

Read the original at Cisco Talos ↗

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