Dell 6.2 Detecting an Omerta Attack, Detecting Rate Anomalies, Detecting a Tkip Replay Attack

Detecting an Omerta Attack

Omerta is an 802.11 DoS tool that sends disassociation frames to all stations on a channel in response to data frames. The Omerta attack is characterized by disassociation frames with a reason code of 0x01. This reason code is “unspecified” and is not be used under normal circumstances.

Detecting Rate Anomalies

Many DoS attacks flood an AP or multiple APs with 802.11 management frames. These can include authenticate/associate frames which are designed to fill up the association table of an AP. Other management frame floods, such as probe request floods, can consume excess processing power on the AP.

Detecting a TKIP Replay Attack

TKIP is vulnerable to replay (via WMM/QoS) and plaintext discovery (via ChopChop). This affects all WPA-TKIP usage. By replaying a captured TKIP data frame on other QoS queues, an attacker can manipulate the RC4 data and checksum to derive the plaintext at a rate of one byte per minute.

By targeting an ARP frame and guessing the known payload, an attacker can extract the complete plaintext and MIC checksum. With the extracted MIC checksum, an attacker can reverse the MIC AP to Station key and sign future messages as MIC compliant, opening the door for more advanced attacks.

Detecting Unencrypted Valid Clients

An authorized (valid) client that is passing traffic in unencrypted mode is a security risk. An intruder can sniff unencrypted traffic (also known as packet capture) with software tools known as sniffers. These packets are then reassembled to produce the original message.

Detecting a Valid Client Misassociation

This feature does not detect attacks, but rather it monitors authorized (valid) wireless clients and their association within the network. Valid client misassociation is potentially dangerous to network security. The four types of misassociation that we monitor are:

•Authorized Client associated to Rogue—A valid client that is associated to a rogue AP

•Authorized Client associated to External AP—An external AP, in this context, is any AP that is not valid and not a rogue

•Authorized Client associated to Honeypot AP—A honeypot is an AP that is not valid but is using an SSID that has been designated as valid/protected

•Authorized Client in ad hoc connection mode—A valid client that has joined an ad hoc network

Detecting an AirJack Attack

AirJack is a suite of device drivers for 802.11(a/b/g) raw frame injection and reception. It was intended to be used as a development tool for all 802.11 applications that need to access the raw protocol, however one of the tools included allowed users to force off all users on an AP.

Detecting ASLEAP

ASLEAP is a tool created for Linux systems which is used to attack Cisco LEAP authentication protocol.

Detecting a Null Probe Response

A null probe response attack has the potential to crash or lock up the firmware of many 802.11 NICs. In this attack, a client probe-request frame will be answered by a probe response containing a null SSID. A number of popular NIC cards will lock up upon receiving such a probe response.

Dell PowerConnect W-Series ArubaOS 6.2 User Guide Wireless Intrusion Prevention 380