New Stealthy Mirai Variant 'Evooo1Bot' Targets Commo...

Executive Summary

A new variant of the notorious Mirai botnet malware, dubbed Evooo1Bot, has been identified in the wild. Security researchers report that this variant has been actively compromising internet-connected devices, particularly common SOHO routers, for at least a month. The botnet spreads by exploiting a series of unpatched vulnerabilities in devices from numerous vendors, including Alcatel, D-Link, Netgear, and Tenda. Evooo1Bot reportedly includes new stealth capabilities, making it more resilient and harder to detect than its predecessors. The emergence of this variant underscores the ongoing threat posed by insecure IoT devices and the continuous evolution of malware designed to exploit them.

Threat Overview

Mirai is a malware family that primarily targets online consumer devices such as routers and IP cameras. It infects them by scanning for open Telnet ports and attempting to log in with a list of common default usernames and passwords. Once infected, the devices become part of a botnet, which is then used to launch powerful Distributed Denial of Service (DDoS) attacks.

The Evooo1Bot variant continues this core functionality but adds two key elements:

Exploitation of Specific Vulnerabilities: In addition to brute-forcing credentials, this variant actively exploits a series of known, unpatched software vulnerabilities in specific router models.
Enhanced Stealth: The variant's code has been modified to include new features designed to evade detection and make removal from the infected device more difficult.

Technical Analysis

The attack chain for Evooo1Bot follows the classic Mirai pattern, with the addition of vulnerability exploitation.

Scanning: The bot scans the internet for potential targets (routers) with open ports or known vulnerabilities.
Infection: The bot attempts to compromise the target either by guessing default credentials or by using a built-in exploit for a specific vulnerability.
Payload Delivery: Upon successful compromise, the bot downloads and executes the main malware payload.
Persistence & C2: The malware establishes persistence, kills competing malware or legitimate services, and connects to a command-and-control (C2) server to await instructions.
Attack: When instructed, the entire botnet of compromised devices floods a target with traffic, causing a DDoS attack.

MITRE ATT&CK TTPs

T1595.002 - Active Scanning: Vulnerability Scanning: The botnet actively scans for vulnerable devices.
T1110.001 - Brute Force: Password Guessing: The traditional Mirai method of trying default credentials.
T1210 - Exploitation of Remote Services: The new addition of exploiting specific firmware vulnerabilities.
T1498 - Network Denial of Service: The ultimate goal of the botnet is to launch DDoS attacks.

Affected Products

The report specifically names routers from the following vendors as being targeted:

Alcatel
D-Link
Netgear
Tenda

Impact Assessment

The primary impact of Mirai and its variants is the ability to launch massive DDoS attacks capable of taking major websites and online services offline. For the owners of the infected devices, the impact includes poor device performance, increased bandwidth usage, and the risk of their device being used in illegal activities. The continuous evolution of Mirai with new exploits and stealth features means that the pool of potential bots is constantly being refreshed, ensuring the longevity of this threat.

IOCs — Directly from Articles

No specific Indicators of Compromise were provided in the source articles.

Cyber Observables — Hunting Hints

For network administrators and home users, the following patterns could indicate an infection:

Type

network_traffic_pattern

Value

Large volume of outbound SYN, UDP, or HTTP floods

Description

This is the classic sign of a device participating in a DDoS attack.

Context

Firewall logs, Netflow analysis, ISP reports

Type

port

Value

23, 2323

Description

Mirai often scans for other devices on Telnet ports 23 and 2323. Outbound traffic on these ports from an IoT device is highly suspicious.

Context

Network monitoring tools

Type

process_name

Value

dvrHelper, xzy, etc.

Description

Mirai often uses common or random process names to disguise itself on the infected device.

Context

Device process list (if accessible)

Detection & Response

Network Monitoring: Monitor for unusual outbound traffic patterns from IoT devices. A device that is suddenly sending a large amount of traffic to a single destination is likely part of a DDoS attack.
Port Scanning: Scan your own network from an external source to identify any unexpectedly open ports on your router or other IoT devices.
Reboot and Patch: A simple reboot can sometimes remove non-persistent malware like some Mirai variants. However, the device will likely be reinfected quickly if the underlying vulnerability is not patched. The correct procedure is to reboot, then immediately log in and apply the latest firmware update.

Mitigation

Update Firmware: Ensure all routers and IoT devices are running the latest firmware from the manufacturer. This is the most effective defense against exploit-based variants like Evooo1Bot. This is a core D3FEND Software Update (D3-SU).
Use Strong, Unique Passwords: Change the default administrator password on all devices to something long and unique. Avoid using simple or common passwords. This aligns with MITRE Mitigation M1027 - Password Policies.
Network Segmentation: Place IoT devices on a separate network segment or VLAN that has restricted access to the internet and to your primary network. This can limit their ability to scan for other victims and prevent them from being used to attack internal devices.

Mirai Variant 'Evooo1Bot' Exploits Unpatched Routers