ASA Packet- tracer Problem

[tareken87]

Hi ,

I have the following problem when i apply packet tracer command:

Result of the command: "packet-tracer input internal tcp 192.168.1.13 25 192.168.3.10 smtp"

Phase: 1
Type: ROUTE-LOOKUP
Subtype: input
Result: ALLOW
Config:
Additional Information:
in   192.168.3.0     255.255.255.0   EXTERNAL

Phase: 2
Type: IP-OPTIONS
Subtype:
Result: ALLOW
Config:
Additional Information:

Phase: 3
Type: INSPECT
Subtype: inspect-smtp
Result: ALLOW
Config:
Additional Information:

Phase: 4
Type: NAT
Subtype:
Result: ALLOW
Config:
object network Mail-Server
 nat (INTERNAL,EXTERNAL) static 192.168.3.10
Additional Information:
Static translate 192.168.1.13/25 to 192.168.3.10/25

Phase: 5
Type: NAT
Subtype: rpf-check
Result: ALLOW
Config:
nat (INTERNAL,EXTERNAL) after-auto source dynamic OBJ_GENERIC_ALL interface
Additional Information:

Result:
input-interface: INTERNAL
input-status: up
input-line-status: up
output-interface: EXTERNAL
output-status: up
output-line-status: up
Action: drop
Drop-reason: (sp-security-failed) Slowpath security checks failed

#################

Result of the command: "show running-config"

ASA Version 8.4(5)
!

interface Ethernet0/0
 nameif INTERNAL
 security-level 100
 ip address 192.168.1.254 255.255.255.0
!
interface Ethernet0/1
 nameif TMG
 security-level 90
 ip address 192.168.2.2 255.255.255.0
!
interface Ethernet0/2
 shutdown
 no nameif
 no security-level
 no ip address
!
interface Ethernet0/3
 nameif EXTERNAL
 security-level 0
 ip address 192.168.3.2 255.255.255.0
!
interface Management0/0
 nameif management
 security-level 100
 ip address 192.168.0.1 255.255.255.0
 management-only
!
ftp mode passive
object network OBJ_GENERIC_ALL
 subnet 0.0.0.0 0.0.0.0
object network Mail-Server
 host 192.168.1.13
access-list EXTERNAL_access extended permit tcp any object Mail-Server eq smtp
pager lines 24
logging asdm informational
mtu INTERNAL 1500
mtu EXTERNAL 1500
mtu management 1500
mtu TMG 1500
icmp unreachable rate-limit 1 burst-size 1
no asdm history enable
arp timeout 14400
no arp permit-nonconnected
!
object network Mail-Server
 nat (INTERNAL,EXTERNAL) static 192.168.3.10
!
nat (INTERNAL,EXTERNAL) after-auto source dynamic OBJ_GENERIC_ALL interface
nat (TMG,EXTERNAL) after-auto source dynamic OBJ_GENERIC_ALL interface
access-group EXTERNAL_access in interface EXTERNAL
route EXTERNAL 0.0.0.0 0.0.0.0 192.168.3.1 1
timeout xlate 3:00:00
timeout pat-xlate 0:00:30
timeout conn 1:00:00 half-closed 0:10:00 udp 0:02:00 icmp 0:00:02
timeout sunrpc 0:10:00 h323 0:05:00 h225 1:00:00 mgcp 0:05:00 mgcp-pat 0:05:00
timeout sip 0:30:00 sip_media 0:02:00 sip-invite 0:03:00 sip-disconnect 0:02:00
timeout sip-provisional-media 0:02:00 uauth 0:05:00 absolute
timeout tcp-proxy-reassembly 0:01:00
timeout floating-conn 0:00:00
dynamic-access-policy-record DfltAccessPolicy
user-identity default-domain LOCAL
http server enable
http 192.168.0.0 255.255.255.0 management
http 192.168.1.0 255.255.255.0 INTERNAL
no snmp-server location
no snmp-server contact
snmp-server enable traps snmp authentication linkup linkdown coldstart warmstart
telnet timeout 5
ssh timeout 5
ssh key-exchange group dh-group1-sha1
console timeout 0
dhcpd address 192.168.0.2-192.168.0.254 management
dhcpd enable management
!
threat-detection basic-threat
threat-detection statistics access-list
no threat-detection statistics tcp-intercept
webvpn
!
class-map inspection_default
 match default-inspection-traffic
!
!
policy-map type inspect dns preset_dns_map
 parameters
  message-length maximum client auto
  message-length maximum 512
policy-map global_policy
 class inspection_default
  inspect dns preset_dns_map
  inspect ftp
  inspect h323 h225
  inspect h323 ras
  inspect rsh
  inspect rtsp
  inspect esmtp
  inspect sqlnet
  inspect skinny  
  inspect sunrpc
  inspect xdmcp
  inspect sip  
  inspect netbios
  inspect tftp
  inspect ip-options
!
service-policy global_policy global
prompt hostname context
no call-home reporting anonymous
Cryptochecksum:d6ec33d7249eec7c088f95b9d3827d9c
: end

My question is what is "sp-security" and why it drop my packets ??

[David Johan Castro Fernandez]

Hello,

Here are the reasons why the packet might be dropped due to this reason:

Name: sp-security-failed

   Slowpath security checks failed:

This counter is incremented and packet is dropped when the security appliance is:

  1) In routed mode receives a through-the-box:

    - L2 broadcast packet

    - IPv4 packet with destination IP address equal to 0.0.0.0

    - IPv4 packet with source IP address equal to 0.0.0.0

  2) In routed or transparent mode and receives a through-the-box IPv4 packet with:

    - first octet of the source IP address equal to zero

    - source IP address equal to the loopback IP address

    - network part of source IP address equal to all 0's

    - network part of the source IP address equal to all 1's

    - source IP address host part equal to all 0's or all 1's

  3) In routed or transparent mode and receives an IPv4 or IPv6 packet with same source        and destination IP addresses

Recommendation:

1 and 2) Determine if an external user is trying to compromise the protected network. Check for misconfigured clients.

3) If this message counter is incrementing rapidly, an attack may be in progress. Use the packet capture feature to capture type asp packets, and check the source MAC address in the packet to see where they are coming from.

Syslogs:

1 and 2) 106016

3) 106017

106016

Error Message %ASA-2-106016: Deny IP spoof from ( IP_address ) to IP_address on interface interface_name.

Explanation A packet arrived at the ASA interface that has a destination IP address of 0.0.0.0 and a destination MAC address of the ASA interface. In addition, this message is generated when the ASA discarded a packet with an invalid source address, which may include one of the following or some other invalid address:

• Loopback network (127.0.0.0)
• Broadcast (limited, net-directed, subnet-directed, and all-subnets-directed)
• The destination host (land.c)

To further enhance spoof packet detection, use the icmp command to configure the ASA to discard packets with source addresses belonging to the internal network, because the access-list command has been deprecated and is no longer guaranteed to work correctly.

Recommended Action Determine if an external user is trying to compromise the protected network. Check for misconfigured clients.

106017

Error Message %ASA-2-106017: Deny IP due to Land Attack from IP_address to IP_address

+ Explanation The ASA received a packet with the IP source address equal to the IP destination, and the destination port equal to the source port. This message indicates a spoofed packet that is designed to attack systems. This attack is referred to as a Land Attack.

+ Recommended Action If this message persists, an attack may be in progress. The packet does not provide enough information to determine where the attack originates.

Please don't forget to rate and mark as correct the Post!

Let me know if there are further questions regarding this

David Castro,

Regards,