AT&T Devices Targeted by EwDoor Botnet
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- By David Lukic
- Published: Dec 17, 2021
- Last Updated: Mar 18, 2022
A botnet dubbed “EwDoor” targets AT&T devices in the United States. The moniker of “EwDoor” was selected as it combines the words Edgewater and backdoor. Botnets are interconnected web-enabled devices that run bots to steal data, transmit spam, conduct Distributed Denial-of-Service (DDoS) attacks and obtain unauthorized access to devices.
How We Learned of the Attack
Netlab researchers (a division of Qihoo 360) first discovered the EwDoor botnet attack. This group states the botnet infected several thousand AT&T devices in the United States.
How Does the Attack Occur?
The infection is implemented using a blind command injection flaw characterized as critically severe. This injection flaw has been around for nearly half a decade. In particular, EwDoor zeroes in on those using EdgeMarc Enterprise Session Border Controller devices that are not properly patched.
Businesses typically use these devices to link their web service providers to enterprise networks for communications in real-time. Examples of such communications include video conferencing and voice calls. The web-facing devices in question link to valuable data, meaning they are a prime target for DDoS attacks, including attempts to harvest data.
When did the Attack Start?
The initial EwDoor attack was identified on the Edgewater Network devices in the last week of October. The specific vulnerability in question is as severe as it gets. This vulnerability can even be weaponized and used for user-defined commands. It is worth mentioning that session border controllers that have default passwords, including a default password and “root” username were compromised in the past.
What was AT&T’s Response?
At the moment, it is not clear if AT&T or Edgewater Networks, the manufacturer of EdgeMarc, revealed the vulnerability in question to AT&T device users in the United States. Ars Technica reports the attack was remedied nearly two years after its initial disclosure. A spokesperson with AT&T states the appropriate steps were taken to “…mitigate it and continue to investigate. We have no evidence that customer data was accessed."
Why the Breach is Important
This digital attack is significant as hackers used the vulnerability in question to transmit a damaging payload. This payload included EwDoor, which was a new botnet at the time.
Once the hackers accessed the auxiliary command-and-control domain, they maintained control for three hours. It was during this time that the digital miscreants gauged the domain’s size. The botnet operators then pivoted to a separate network model for communication.
The end result of the attack was an infection of nearly 6,000 devices. Each of these devices is located in the United States. The EwDoor evolved in three distinct updates, enhancing its functionality to DDoS attacks and backdoor entry. The researchers who identified the breach suspect the hack accessed user call logs and other sensitive information. The fear is this sensitive information has since been sold on the black market.
