ch05 deel

05_post_exploitation.md

@@ -95,3 +95,92 @@
         * ask target personnel for info on policy
         * create test account for pentest
         * attempt 1 password per observation window
+
+## Password representation
+
+* Windows
+    * Security Accounts Manager (SAM) for modern desktop versions
+        * stores all local account info
+        * login info from domain users that connected to the machine
+        * encrypted SAM database
+        * password hashes stored in registry
+    * LANMAN (LM) or NT hashes
+    * Active Directory newer alternative
+
+### Lanman hash
+
+* operation
+    1. truncate password to 14 characters (pad with NUL bytes if less)
+    2. convert to uppercase
+    3. split into two 7-char pieces
+    4. use each piece as 7-byte DES key to encrypt 64-bit known constant `KGS!@#$%`
+    5. hash is concatenation of two 8-byte outputs
+* this hash is criminally bad
+
+### NT hash
+
+* operation
+    1. convert password (max 256 chars) into UTF-16 little endian format
+    2. hash using MD4 (no salt)
+* better but still pretty bad
+
+## Windows challenge-reponse authentication
+
+* mutiple forms of network cryptographic authentication
+    * **LANMAN challenge/response**: legacy-only, uses LM hash
+    * **NTLMv1**: also legacy, uses NT hash
+    * **NTLMv2**: stronger security, uses NT hash
+    * **Microsoft Kerberos**
+
+### LANMAN and NTLMv1
+
+* operation
+    1. client initiates authentication
+    2. server sends 8-byte challenge
+    3. client formulates response
+        1. pad LM/NT hash to 21 bytes
+        2. split hash in three 7-byte pieces
+        3. use each piece as DES key to encrypt challenge
+        4. response is 3 8-byte outputs
+    4. server calculates same response and compares
+* problems
+    * attacker can sniff both challenge and response and try to crack
+    * rogue server could issue static challenge for which it has rainbow tables
+        * works because neither hash uses salting
+    * without rogue server, method is slower than cracking hashes in SAM db
+        * no access to actual hash
+        * attacker needs to perform DES encryption
+
+### NTLMv2
+
+* operation
+    1. client sends authentication request
+    2. server sends 8-byte server challenge
+    3. client formulates response
+        1. creates NTLMv2 hash using HMAC-MD5
+            * data: username and domain name
+            * key: NT hash
+        2. creates NTLMv2 response using HMAC-MD5
+            * data: server challenge + data blob (client challenge, timestamp,
+              fields for integrity / security)
+            * key: NTLMv2 hash
+    4. client sends response to server
+    5. server computes validity of response using stored NT hash and received
+    fields
+* cracking still possible but much slower
+    * stronger hash is used
+    * timestamp protects against replay attacks
+    * rainbow tables not useful due to variability of client challenge
+
+### NTLM relay attacks
+
+* both versions vulnerable
+* possible if attacker can access server client usually uses
+    * ARP or DNS spoofing
+    * phishing
+    * cross-site scripting attacks
+* operation
+    1. attacker poses as authentication server
+    2. attacker relays authentication request messages to real server -> acts
+       as authenticating client
+    3. attacker receives authentication and returns error message to client