BlueLock - bi0sCTF22 AmunRha 2023-02-10 Reversing / Windows tl;dr Implemented two SEH and two VEH Exception Handlers Two stage malware challenge with process injection technique CPP binary where logic is wrapped in classes and their member functions Read More Windows bi0sCTF Reversing ExceptionHandling
kawaii_vm - bi0sCTF 2022 k1R4 2023-01-25 Pwn tl;dr Giving custom array size of NaN, passes checks while allowing OOB r/w Use OOB r/w to get libc, stack (environ) addresses Craft fake chunk on array and overwrite fastbin fd Reset machine to allocate register context on fake chunk Overwrite VM sp with real stack Push ropchain onto stack and halt VM to execute ropchain Read More Exploitation VM bi0sCTF
k32 - bi0sCTF 2022 k1R4 2023-01-23 Pwn tl;dr Giving size > 48 causes heap OOB r/w of 16 bytes Use OOB r/w get leaks and overwrite objects for rip control Read More Heap Exploitation Kernel bi0sCTF
b3typer - bi0sCTF 2022 d4rk_kn1gh7 2023-01-23 Pwn tl;dr Simple typer bug, range of BitAnd opcode is assumed to be [1, operand] when in reality it is [0, operand]. Use range assumptions to create unchecked integer underflow. Bypass array bounds checks and obtain OOB write, overwrite size of array to get overlap. Use double & object array overlap to create addrOf & fakeObj primitives. Create overlapping fake array using StructureID leak to obtain arbitrary R/W. Read More Exploitation Browser Safari bi0sCTF