Add first version of crack linux pass app

crack/crack.py

@@ -0,0 +1,65 @@
+import re
+import sys
+
+from passlib.hash import sha512_crypt
+
+DEF_ROUNDS = 5000
+
+
+def parse_crypt_line(cr_line: str):
+    p_cr_pass = cr_line.split("$", 3)
+    if len(p_cr_pass) < 3:
+        return None, None, None
+    _, alg, salt, passwd = p_cr_pass
+    return alg, salt, passwd
+
+
+def brute_passwd(dict_file, cr_line):
+    alg, salt, passwd = parse_crypt_line(cr_line)
+    if not passwd:
+        return None
+    r_match = re.match(r".*rounds=(\d*)", salt)
+    rounds = r_match.group(1) if r_match else DEF_ROUNDS
+
+    with open(dict_file, 'r') as df:
+        for line in df.readlines():
+            open_pass = line.strip()
+            exp_pass = sha512_crypt.hash(open_pass, salt=salt, rounds=rounds)
+            if exp_pass == cr_line:
+                return open_pass
+    return None
+
+
+def parse_shadow(shadow_file):
+    result = dict()
+
+    with open(shadow_file, 'r') as sf:
+        for line in sf.readlines():
+            p_line = line.split(":")
+            if len(p_line) < 2:
+                continue
+            user, cr_pass = p_line[:2]
+            if not all(parse_crypt_line(cr_pass)):
+                continue
+            result[user] = cr_pass
+
+    return result
+
+
+def main():
+    if len(sys.argv) != 3:
+        print(f"Usage: {sys.argv[0]} <shadow_file> <dictionary>")
+        exit(0)
+    shadow = sys.argv[1]
+    dictionary = sys.argv[2]
+
+    shadow_data = parse_shadow(shadow)
+    for user, cr_pass in shadow_data.items():
+        found_pass = brute_passwd(dictionary, cr_pass)
+        if found_pass:
+            print(f"[+] Found password for {user}: {found_pass}")
+            continue
+
+
+if __name__ == "__main__":
+    main()

requirements.txt

@@ -1 +1,2 @@
 ipython
+passlib