The Zerobot DDoS botnet has received substantial updates that expand on its ability to target more internet-connected devices and scale its network.

Microsoft Threat Intelligence Center (MSTIC) is tracking the ongoing threat under the moniker DEV-1061, its designation for unknown, emerging, or developing activity clusters.

Zerobot, first documented by Fortinet FortiGuard Labs earlier this month, is a Go-based malware that propagates through vulnerabilities in web applications and IoT devices like firewalls, routers, and cameras.

"The most recent distribution of Zerobot includes additional capabilities, such as exploiting vulnerabilities in Apache and Apache Spark (CVE-2021-42013 and CVE-2022-33891 respectively), and new DDoS attack capabilities," Microsoft researchers said.

Also called ZeroStresser by its operators, the malware is offered as a DDoS-for-hire service to other criminal actors, with the botnet advertised on social media by its operators.

Microsoft said that one domain with connections to Zerobot – zerostresser[.]com – was among the 48 domains that were seized by the U.S. Federal Bureau of Investigation (FBI) this month for offering DDoS attack features to paying customers.

The latest version of Zerobot spotted by Microsoft not only targets unpatched and improperly secured devices, but also attempts to brute-force over SSH and Telnet on ports 23 and 2323 for spreading to other hosts.

The list of newly added known flaws exploited by Zerobot 1.1 is as follows -

• CVE-2017-17105 (CVSS score: 9.8) - A command injection vulnerability in Zivif PR115-204-P-RS
• CVE-2019-10655 (CVSS score: 9.8) - An unauthenticated remote code execution vulnerability in Grandstream GAC2500, GXP2200, GVC3202, GXV3275, and GXV3240
• CVE-2020-25223 (CVSS score: 9.8) - A remote code execution vulnerability in the WebAdmin of Sophos SG UTM
• CVE-2021-42013 (CVSS score: 9.8) - A remote code execution vulnerability in Apache HTTP Server
• CVE-2022-31137 (CVSS score: 9.8) - A remote code execution vulnerability in Roxy-WI
• CVE-2022-33891 (CVSS score: 8.8) - An unauthenticated command injection vulnerability in Apache Spark
• ZSL-2022-5717 (CVSS score: N/A) - A remote root command injection vulnerability in MiniDVBLinux

Upon successful infection, the attacks chain proceeds to download a binary named "zero" for a specific CPU architecture that enables it to self-propagate to more susceptible systems exposed online.

Additionally, Zerobot is said to proliferate by scanning and compromising devices with known vulnerabilities that are not included in the malware executable, such as CVE-2022-30023, a command injection vulnerability in Tenda GPON AC1200 routers.

Zerobot 1.1 further incorporates seven new DDoS attack methods by making use of protocols such as UDP, ICMP, and TCP, indicating "continuous evolution and rapid addition of new capabilities."

"The shift toward malware as a service in the cyber economy has industrialized attacks and has made it easier for attackers to purchase and use malware, establish and maintain access to compromised networks, and utilize ready-made tools to perform their attacks," the tech giant said.