Bryce Kerley firstname.lastname@example.org
This challenge binary requires the solver to provide inputs for an algorithm that uses mixed floating point and integer operations on its inputs.
The service opens with a simple "hello" message that must be returned by the client.
The client then sends 32 bits of input to the server, which is expanded using a custom RNG algorithm using mixed floating-point and integer operations. The algorithm then takes more input, for a total of 256 bits of input, to reach an end state matching certain hardcoded properties.
Once the end state has been reached, the client is provided access to a set data structure implemented as a bitmap on the stack. However, the address space of the structure is larger than its capacity, allowing stack writes outside of its bounds.
The set data structure on the stack has incorrect bounds checking, allowing user control of individual bits above it on the stack.
CWE-129 Improper Validation of Array Index
The primary difficulty with this challenge is solving for specific outputs with mixed floating-point and integer operations.
Curated by Lunge Technology, LLC. Questions or comments? Send us email