> For the complete documentation index, see [llms.txt](https://wiki.zacheller.dev/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://wiki.zacheller.dev/exploit-dev-analysis/static-analysis/packed-and-obfuscated-malware/demo-upx.md).

# Demo: UPX

Choose a file that contains strings, and run:

* upx -o \<packedFileName> \<fileToPack>
* strings \<fileToPack> | wc
* strings \<packedFileName> | wc

What do you see?

```
$ strings test_malware.exe
# full words and potential error messages

$ upx -o packed test_malware.exe

$ strings packed
# no human-readable strings

$ strings test_malware.exe | wc
700 1978 15062

$ strings packed | wc
659 716 4029
```