OP_LOAD reg, value // load immediate OP_STORE reg, offset // store to memory OP_ADD reg1, reg2 OP_JMP offset OP_CALL func_id
Some VMs implement a "syscall" instruction that passes arguments to the host syscall function or libc equivalents. OP_LOAD reg, value // load immediate OP_STORE reg,
| Vulnerability | Description | |---------------|-------------| | | Index into VM memory array not validated | | Type confusion | Treating integer as pointer (e.g., storing real addresses in registers) | | Use-after-free | VM manages heap objects (strings, arrays) without proper refcounting | | Infinite loop / DoS | Control flow opcodes miss checks | | Memory leak | Uninitialized memory disclosure → bypass ASLR | | Arbitrary read/write primitive | Combining bugs to read/write anywhere in process memory | value // load immediate OP_STORE reg
Return Oriented Programming used after escaping the VM to bypass modern OS protections. OP_LOAD reg, value // load immediate OP_STORE reg,