int3E8

Int3E8 is not a standard term in official documentation, but it is sometimes used in security research and reverse engineering to describe a small x86 machine-code sequence consisting of the INT 3 instruction followed by a near CALL instruction. The two relevant opcodes are 0xCC for INT 3 and 0xE8 for a relative near call. When encountered in a binary or shellcode, this pattern is read as two consecutive instructions: a breakpoint trap and then a call to a target address computed from the subsequent displacement.

Int 3 (0xCC) is a debugging aid that triggers a breakpoint exception, typically causing a debugger to pause execution and allow inspection of state. The subsequent near call (0xE8) changes control flow by pushing the return address and jumping to a function or payload specified by the following 32-bit relative displacement. In practice, the sequence can serve multiple purposes: it can pause execution in a controlled debugging context, or be used in obfuscated or self-modifying code to complicate static analysis and then transfer control to a payload after the breakpoint is handled.

In use, the exact effect depends on the execution environment and whether a debugger is attached. In malware analysis and exploit development, the 0xCC 0xE8 pattern may be observed as part of a compact payload or as a hurdle for static disassembly, since the breakpoint can disrupt straightforward interpretation until a debugger or exception handler is engaged. Analysts typically disassemble and, if needed, emulate or trace the code to understand the intended control flow.

See also: INT 3 instruction; CALL (x86) instruction; shellcode; obfuscation techniques.