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feat: adding cooldown to alerts + more precise pattern matching for TCP

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This commit is contained in:
Oxbian
2024-11-19 16:42:08 -05:00
parent 48e9554d38
commit 3e75cb8927
3 changed files with 77 additions and 40 deletions
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19
idps/rules/TCP/Scan/synscan.py
View File

@ -1,4 +1,6 @@
from datetime import datetime
import time
def rule(packet, tcp_packets, db):
"""Règle SYNScan:
@ -6,10 +8,21 @@ def rule(packet, tcp_packets, db):
Si le port est ouvert alors le serveur répondra: Syn ACK, puis le client Reset la connexion
Sinon le port est fermé et le serveur répondera: Reset ACK
"""
if (rule.cooldown + rule.time_window > time.time()):
return
time_window = db.get_key("synscan_time", 180)
seuil = db.get_key("synscan_count", 5)
# Vérification si nécessaire de récupérer les variables depuis la config
if (rule.seuil == 0 and rule.time_window == 0):
rule.time_window = db.get_key("synscan_time", 180)
rule.seuil = db.get_key("synscan_count", 5)
if (tcp_packets.count_packet_of_type("RA", time_window) + tcp_packets.count_packet_of_type("SA", time_window)) + tcp_packets.count_packet_of_type("R", time_window) >= seuil:
if tcp_packets.count_packet_of_type(["S", "RA"], rule.time_window, True) + tcp_packets.count_packet_of_type(["S", "SA", "RA"], rule.time_window, True) >= rule.seuil:
db.send_alert(datetime.now(), 5, None, "Syn scan", packet['IP'].src, packet['IP'].dst, proto="TCP", reason="Détection de nombreux patterns de Syn->SynACK->Reset ACK et Syn->Reset ACK", act="Alerte")
print(f"Alerte, seuil dépassés, risque de SynScan")
rule.cooldown = time.time()
# Variables statiques
rule.cooldown = 0
rule.time_window = 0
rule.seuil = 0

21
idps/rules/TCP/Scan/tcpconnectscan.py
View File

@ -1,4 +1,6 @@
from datetime import datetime
import time
def rule(packet, tcp_packets, db):
"""Règle TCPConnect Scan:
@ -6,9 +8,22 @@ def rule(packet, tcp_packets, db):
Si le port est ouvert le serveur acceptera la connexion SYN -> SYN ACK -> ACK -> Reset -> ACK
Sinon le port est fermé et le serveur refusera la connexion SYN -> Reset ACK
"""
time_window = db.get_key("tcpconnectscan_time", 180)
seuil = db.get_key("tcpconnectscan_count", 5)
if (tcp_packets.count_packet_of_type("A", time_window) + tcp_packets.count_packet_of_type("RA", time_window)) >= seuil:
if (rule.cooldown + rule.time_window > time.time()):
return
# Vérification si nécessaire de récupérer les variables depuis la config
if (rule.seuil == 0 and rule.time_window == 0):
rule.time_window = db.get_key("tcpconnectscan_time", 180)
rule.seuil = db.get_key("tcpconnectscan_count", 5)
if tcp_packets.count_packet_of_type(["S", "SA", "A", "RA"], rule.time_window, True) + tcp_packets.count_packet_of_type(["S", "RA"], rule.time_window, True) >= rule.seuil:
db.send_alert(datetime.now(), 5, None, "TCPConnect Scan", packet['IP'].src, packet['IP'].dst, proto="TCP", reason="Détection de nombreux patterns de Syn->SynACK->ACK->Reset->ACK et Syn->Reset ACK", act="Alerte")
print(f"Alerte, seuils dépassés, risque de TCPConnectScan")
rule.cooldown = time.time()
# Variables statiques
rule.cooldown = 0
rule.time_window = 180
rule.seuil = 5

73
idps/tcp.py
View File

@ -19,74 +19,81 @@ class TCP:
self.packets[ip_src] = []
if flags == "S":
self.packets[ip_src].append([port_src, ip_dst, port_dst, [flags], timestamp])
self.packets[ip_src].append([port_src, ip_dst, port_dst, ["S"], timestamp])
return
elif flags == "SA":
i = self.find_packet_to_replace(ip_src, port_src, ip_dst, port_dst, "S", True)
i, ip = self.find_packet_to_replace(ip_src, port_src, ip_dst, port_dst, "S")
if i is not None:
self.packets[ip_dst][i][3].append("SA")
self.packets[ip_dst][i][4] = timestamp
print(f"i: {i}, {ip_src}:{port_src}->{ip_dst}:{port_dst}, paquets: \n{self.packets}")
self.packets[ip][i][3].append("SA")
self.packets[ip][i][4] = timestamp
return
else:
self.packets[ip_src].append([port_src, ip_dst, port_dst, [flags], timestamp])
self.packets[ip_src].append([port_src, ip_dst, port_dst, ["SA"], timestamp])
return
elif flags == "A":
i = self.find_packet_to_replace(ip_src, port_src, ip_dst, port_dst, "SA")
i, ip = self.find_packet_to_replace(ip_src, port_src, ip_dst, port_dst, "SA")
if i is None:
i = self.find_packet_to_replace(ip_src, port_src, ip_dst, port_dst, "R", True)
i, ip = self.find_packet_to_replace(ip_src, port_src, ip_dst, port_dst, "R")
if i is not None:
self.packets[ip_src][i][3].append("A")
self.packets[ip_src][i][4] = timestamp
print(f"i: {i}, {ip_src}:{port_src}->{ip_dst}:{port_dst}, paquets: \n{self.packets}")
self.packets[ip][i][3].append("A")
self.packets[ip][i][4] = timestamp
return
else:
self.packets[ip_src].append([port_src, ip_dst, port_dst, [flags], timestamp])
self.packets[ip_src].append([port_src, ip_dst, port_dst, ["A"], timestamp])
return
elif flags == "RA":
i = self.find_packet_to_replace(ip_src, port_src, ip_dst, port_dst, "A")
i, ip = self.find_packet_to_replace(ip_src, port_src, ip_dst, port_dst, "A")
if i is None:
i = self.find_packet_to_replace(ip_src, port_src, ip_dst, port_dst, "S")
i, ip = self.find_packet_to_replace(ip_src, port_src, ip_dst, port_dst, "S")
if i is not None:
self.packets[ip_src][i][3].append("RA")
self.packets[ip_src][i][4] = timestamp
print(f"i: {i}, {ip_src}:{port_src}->{ip_dst}:{port_dst}, paquets: \n{self.packets}")
self.packets[ip][i][3].append("RA")
self.packets[ip][i][4] = timestamp
return
else:
self.packets[ip_src].append([port_src, ip_dst, port_dst, [flags], timestamp])
self.packets[ip_src].append([port_src, ip_dst, port_dst, ["RA"], timestamp])
return
elif flags == "R":
i = self.find_packet_to_replace(ip_src, port_src, ip_dst, port_dst, "A")
i, ip = self.find_packet_to_replace(ip_src, port_src, ip_dst, port_dst, "A")
if i is None:
i = self.find_packet_to_replace(ip_src, port_src, ip_dst, port_dst, "S")
i, ip = self.find_packet_to_replace(ip_src, port_src, ip_dst, port_dst, "S")
if i is not None:
self.packets[ip_src][i][3].append("R")
self.packets[ip_src][i][4] = timestamp
print(f"i: {i}, {ip_src}:{port_src}->{ip_dst}:{port_dst}, paquets: \n{self.packets}")
self.packets[ip][i][3].append("R")
self.packets[ip][i][4] = timestamp
return
else:
self.packets[ip_src].append([port_src, ip_dst, port_dst, [flags], timestamp])
self.packets[ip_src].append([port_src, ip_dst, port_dst, ["R"], timestamp])
return
def find_packet_to_replace(self, ip_src, port_src, ip_dst, port_dst, flags, reverse=False):
"""Cherche l'indice du paquet dont le flag doit être remplacé"""
if reverse is True:
ip_src, ip_dst = ip_dst, ip_src
port_src, port_dst = port_dst, port_src
if ip_src not in self.packets.keys():
return None
def find_packet_to_replace(self, ip_src, port_src, ip_dst, port_dst, flags):
"""Cherche l'indice et le port de source du paquet dont le flag doit être remplacé"""
# Recherche dans le sens src->dst
if ip_src in self.packets.keys():
for i, [p_s, ip_d, p_d, f, stamp] in enumerate(self.packets[ip_src]):
if p_s == port_src and ip_d == ip_dst and p_d == port_dst and flags in f:
return i
return None
return i, ip_src
# Recherche dans le sens dst->src
if ip_dst in self.packets.keys():
for i, [p_d, ip_s, p_s, f, stamp] in enumerate(self.packets[ip_dst]):
if p_s == port_src and ip_s == ip_src and p_d == port_dst and flags in f:
return i, ip_dst
return None, None
def clean_old_packets(self):
"""Supprime les paquets qui date de plus longtemps que le temps de clean"""
@ -108,14 +115,16 @@ class TCP:
if not self.packets[ip_src]:
del self.packets[ip_src]
def count_packet_of_type(self, flag, time_treshold):
def count_packet_of_type(self, flag, time_treshold, isList = False):
"""Compte les paquets qui ont le flag choisi et qui sont dans la fenêtre de temps"""
count = 0
current_timestamp = time.time()
for ip in list(self.packets.keys()):
for packet in self.packets[ip]:
if flag in packet[3] and packet[4] >= current_timestamp - time_treshold:
if isList and set(flag) == set(packet[3]) and packet[4] >= current_timestamp - time_treshold:
count += 1
elif not isList and flag in packet[3] and packet[4] >= current_timestamp - time_treshold:
count += 1
return count