https://github.com/asutoshpalai/de-jsfuck
It deobfuscates JSFuck into readable JavaScript
https://github.com/asutoshpalai/de-jsfuck
common-lisp javascript jsfuck
Last synced: 3 days ago
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It deobfuscates JSFuck into readable JavaScript
- Host: GitHub
- URL: https://github.com/asutoshpalai/de-jsfuck
- Owner: asutoshpalai
- License: gpl-3.0
- Created: 2017-03-25T18:37:08.000Z (about 8 years ago)
- Default Branch: master
- Last Pushed: 2018-02-27T04:25:52.000Z (over 7 years ago)
- Last Synced: 2025-03-24T01:01:43.250Z (3 months ago)
- Topics: common-lisp, javascript, jsfuck
- Language: Common Lisp
- Homepage:
- Size: 27.3 KB
- Stars: 40
- Watchers: 1
- Forks: 6
- Open Issues: 1
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Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# de-jsfuck
It deobfuscates JSFuck into readable JavaScript.
## Quick use guide
_If you have already setup SBCL with Quicklisp, the you can skip installing Roswell_
- Install and setup [Roswell](https://github.com/roswell/roswell#installation-dependency--usage)
- Run
$ ./run.sh ''
## Background details
I had to get past some changing JSFuck code which injected some global variables and
get the values of those variables. My target was to reverse a JSFuck code with only
specific part varying every time. So, I embarked upon the strategy of pattern matching.
In the end, I was able to decode almost all of the JSFuck code.
The important observations on which the code is based are
- All codes began with a specific pattern which fetched `Function` of JS which
is used to generate functions from strings.
- All of them ended with () which called the generated function.
- The code between them had segments enclosed within () of [], sometimes
continuous, separated by +. They turned out to generate characters of the
string being concatenated with +.
Note: _I have added only those characters which I encountered during my inspection. The
token list is not complete. If you find `