Impossible Disassembly
Created the Monday 18 March 2019. Updated 2 weeks, 1 day ago.
Impossible disassembly is an anti-disassembling technique that involves inserting data bytes after a conditional jump instruction in order to prevent the real instruction that follows from being disassembled. This technique takes advantage of a basic assumption in disassembly, which states that one byte is only interpreted in the context of one instruction. By inserting a byte that is the opcode for a multibyte instruction, the disassembler will be unable to correctly interpret the next instruction, and will therefore generate incorrect disassembly output.
Technique Identifier
Code Snippets
Detection Rules
Additional Resources
External Links
The resources provided below are associated links that will give you even more detailed information and research on current evasion technique. It is important to note that, while these resources may be helpful, it is important to exercise caution when following external links. As always, be careful when clicking on links from unknown sources, as they may lead to malicious content.
- Practical Malware Analysis: Ch 15: Anti-Disassembly
- https://medium.com/swlh/assembly-wrapping-a-new-technique-for-anti-disassembly-c144eb90e036
- Anti-disassembly with a rogue byte | Gelven's Blog