CVE-2024-48990 PoC — needrestart 安全漏洞

介绍

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CVE-2024-48990 (and CVE-2024-48992)
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To determine whether a Python process (a process that is running the
Python interpreter) needs to be restarted, needrestart extracts the
PYTHONPATH environment variable from this process's /proc/pid/environ
(at line 193), sets this environment variable if it exists (at line
196), and executes Python ("$ptable->{exec}" at line 203) with a "-"
argument to read a short, hard-coded script from stdin (at line 204):

------------------------------------------------------------------------
""" perl
135 sub files {
136     my $self = shift;
137     my $pid = shift;
138     my $cache = shift;
139     my $ptable = nr_ptable_pid($pid);
...
193     my %e = nr_parse_env($pid);
194     local %ENV;
195     if(exists($e{PYTHONPATH})) {
196         $ENV{PYTHONPATH} = $e{PYTHONPATH};
197     }
...
203     my ($pyread, $pywrite) = nr_fork_pipe2($self->{debug}, $ptable->{exec}, '-');
204     print $pywrite "import sys\nprint(sys.path)\n";
205     close($pywrite);
"""
------------------------------------------------------------------------

Unfortunately, if a Python process belongs to a local attacker, then
needrestart executes Python (at line 203) with an attacker-controlled
PYTHONPATH environment variable, which allows the attacker to execute
arbitrary code as root (even though needrestart's hard-coded Python
script at line 204 is not attacker-controlled at all). This is
CVE-2024-48990.

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