VHT is a feature of 802.11n that allows the receiver to know the number of the sending station the instant it receives an access point (AP) frame with a high-order address. The receiver needs to know the number of the AP in order to know the distance to it and hence avoid flooding it with unnecessary traffic. If there is a malfunction in the AP or the receiver does not process VHT correctly, it can result in an out-of-bound read and denial of service. To detect if this is the case on your device, go to Settings -> About phone -> Software information. If the diagnostic information states that VHT is turned on, then this is the recommended course of action. To turn VHT off, go to Settings -> Network -> Advanced settings -> 802.11n VHT -> OFF.
Incorrect handling of VHT can also result in denial of service. If the VHT information is not processed correctly, then it can cause an out-of-bound read when an AP sends a frame with a high-order address of the receiver. This can lead to denial of service. To prevent this, make sure that the receiver handles VHT correctly.
Finding Network Information with VHT
With VHT, the receiver can determine its distance to an AP. The receiver needs to know the number of the AP in order to know how far away it is and avoid flooding it with unnecessary traffic. To find out if this is on your device, go to Settings -> About phone -> Software information. If a diagnostic information states that VHT is turned on, then make sure that you handle this feature correctly by going to Settings -> Network -> Advanced settings -> 802.11n VHT -> OFF.
Detect if VHT is enabled and disabled
This article discusses how to check if 802.11n VHT is enabled or disabled on a device. The diagnostic information found in the settings menu can help you to determine if 802.11n VHT is enabled or disabled.
Incorrect handling of 802.11n VHT can also lead to denial of service. If 802.11n VHT is not processed correctly, then it can cause an out-of-bound read when an AP sends a frame with a high-order address of the receiver, which results in denial of service. To prevent this, make sure that the receiver handles 802.11n VHT correctly and does not process it incorrectly by turning off excessive traffic from the network when an AP receives it incorrectly.
VHT Operation
There are two possible states for VHT operation. If the diagnostic information indicates that VHT is turned on, then it means that VHT is in its peak state or the state where it can fully operate. To turn off VHT, change the setting from a peak state to OFF.
If the diagnostic information indicates that VHT is off or it has entered into a reduced state, then it means that there has been some malfunction and the receiver cannot process VHT frames correctly. This can lead to an out-of-bound read when an AP sends a frame with a high-order address of the receiver. In this case, you should contact technical support to fix this problem.
Mitigations for VHT Denial of Service Attacks
To prevent denial of service attacks, make sure that VHT is not turned on. If you have VHT turned on but it does not appear in the software information, then it's possible that the receiver has a malfunction or a bug.
VHT is turned on on your device
If your device is exhibiting any of the symptoms mentioned above, then it is recommended that you turn VHT off. To turn VHT off, go to Settings -> Network -> Advanced settings -> 802.11n VHT -> OFF.
Timeline
Published on: 10/19/2022 11:15:00 UTC
Last modified on: 10/20/2022 20:48:00 UTC