Tcp null misuse attack

Packets contain IPv4 headers which carry information about which Transport Protocol is being used. When the target server tries to put process these packets, it will eventually exhaust its resources and reboot.

It is a very old protocol which can be exploited to execute amplified attacks. These spoofed requests to such devices are then used to send UDP floods as responses from these devices to the target.

Most internet-enabled printers, copiers etc. This can be used to flood a target with UDP packets on port When the target tries to make sense of these requests, it will fail to do so. The server will eventually exhaust its resources and go offline or reboot. SNMP is mainly used on network devices. When the target tries to make sense of this flood of requests, it will end up exhausting its resources and go offline or reboot.

The NTP protocol is another publicly accessible network protocol. The SSDP amplification attack is also carried out by sending small packets carrying a spoofed IP of the target to devices. These spoofed requests to such devices are used to send UDP floods as responses from these devices to the target. Other UDP protocols that have been identified as possible tools for carring out amplification flood attacks U.

CERT are:. Then, HTTP packets are split by the bot into tiny fragments and sent to the target as slowly as it allows before it times out. This method allows the attackers to keep a connection active for a long time without alerting any defense mechanisms.

An attacker can use one BOT to initiate several undetected, extended and resource consuming sessions. Popular web servers like Apache do not have effective timeout mechanisms. An attacker can exploit a loophole in HTTP 1. This allows attackers to send a large number of requests from a handful of sessions. In other words, attackers can bypass the limitations imposed by DDoS defense mechanisms on the number of sessions allowed.

When defense mechanisms evolved to block many incoming packets, attacks like Single Packet HTTP Flood were designed with workarounds to dodge these defenses. For an attack to be highly successful, it must remain undetected for as long as possible. The best method to go undetected is to appear as a legitimate request by staying within all the limitations while another attack is being executed. Recursive GET achieves this on its own by collecting a list of pages or images and appearing to be going through these pages or images.

This attack is a purpose built variation of Recursive GET attack. It is designed for forums, blogs and other websites that have pages in a sequence. Like Recursive GET it also appears to be going through pages.

Since page names are in a sequence, to keep up appearance as a legitimate user, it uses random numbers from a valid page range to send a new GET request each time. Attacks can also combine several methods to keep the engineers dealing with the DDoS attack confused. These attacks are the toughest to deal with and are capable of taking down some of the best-protected servers and networks. This attack exploits the design of the three-way TCP communication process between a client, host, and a server.

In this process, a client initiates a new session by generating a SYN packet. Resources Required. Packet injection tools are also useful for this purpose. Depending upon the method used it may be necessary to sniff the network in order to see the response. This table specifies different individual consequences associated with the attack pattern. The Scope identifies the security property that is violated, while the Impact describes the negative technical impact that arises if an adversary succeeds in their attack.

The Likelihood provides information about how likely the specific consequence is expected to be seen relative to the other consequences in the list. For example, there may be high likelihood that a pattern will be used to achieve a certain impact, but a low likelihood that it will be exploited to achieve a different impact.

Scope Impact Likelihood Confidentiality. Related Weaknesses. A Related Weakness relationship associates a weakness with this attack pattern. Each association implies a weakness that must exist for a given attack to be successful. If multiple weaknesses are associated with the attack pattern, then any of the weaknesses but not necessarily all may be present for the attack to be successful. Each related weakness is identified by a CWE identifier. Some operating systems, like Microsoft Windows, send a RST packet in response to any out-of-sync or malformed TCP segments received by a listening socket rather than dropping the packet via RFC , thus preventing the adversary from distinguishing between open and closed ports.

NULL scans are limited by the range of platforms against which they work. Chapter 2: Scanning, pg. McGraw Hill. Section 5. If we see a high volume of such traffic destined to many different IP addresses, it means somebody is probably performing UDP ping sweeping to find alive hosts on the network e.

This section contains Wireshark filters useful for identifying various network port scans, port sweeps etc. The small window size in particular is the characteristic parameter used by tools such as nmap or massscan during SYN scans, indicating that there will be essentially very little or no data. TCP Null scanning works by sending packets without any flags set. This could potentially penetrate some of the firewalls and discover open ports.

If we see packets like this in our network, someone is probably performing TCP null scans e. This could again potentially penetrate some of the firewalls and discover open ports. This is yet another technique of penetrating some of the firewalls to discover open ports. If we see such packets in our network, someone is probably performing TCP Xmass scans e.

If we see a high number of these packets in our network in a short period of time, it most likely means someone is doing UDP port scans e. This section contains Wireshark filters useful for identifying various network attacks such as poisoning attacks, flooding, VLAN hoping etc. This filter will display any occurrence of a single IP address being claimed by more than one MAC address. Such situation likely indicates that ARP poisoning is happening in our network.

ARP poisoning also known as ARP spoofing is a technique used to intercept network traffic between the router and other clients on the local network. It allows the attacker to perform man-in-the-middle MitM attacks on neigboring computers on the local network using tools such as arpspoof , ettercap and others.

A typical standard ICMP ping sends packets with 32 bytes of data ping command on Windows or 48 bytes ping command on Linux. When someone is doing ICMP flood, they typically send much larger data, so here we are filtering all ICMP packets with data size of more than 48 bytes.

Adversaries typically use tools such as fping or hping to perform ICMP flooding. If we see such packets in our network, someone might be attempting to do VLAN hoping e. If we see many packet re-transmissions and gaps in the network communication missing packets , it may indicate that there is a severe problem in the network, possibly caused by a denial of service attack.