---
title: 'Sonic1: Mirai Variant Targeting Multiple Vulnerabilities'
url: https://www.emergentmind.com/topics/sonic1
type: topic
---

# Sonic1: Mirai Variant Targeting Multiple Vulnerabilities

Sonic1 denotes a Mirai-derived IoT botnet variant discussed under the shorter label **Sonic** in “Analyzing The Mirai IoT Botnet and Its Recent Variants: Satori, Mukashi, Moobot, and Sonic” [2508.01909]. In that account, Sonic is an unnamed Mirai variant observed in **February 2021** and unofficially named by the authors because one of its key targets is a **SonicWall SSL-VPN vulnerability**. Its significance lies less in quantified botnet scale than in its exploit breadth: the variant is described as targeting **six recently discovered vulnerabilities** across multiple vendors, alongside **three additional unidentified command-injection vulnerabilities**, with the introduction further stating that it “continues to utilize three zero-day vulnerabilities” [2508.01909]. A plausible implication is that the label “Sonic1” is a later naming convenience for the same botnet that the paper calls Sonic.

## 1. Designation, discovery, and placement within the Mirai lineage

Sonic1 is treated as one of four “recent” Mirai variants, together with Satori, Mukashi, and Moobot [2508.01909]. The paper states that there was **no official name** for the botnet at the time of writing, and that the designation **Sonic** was adopted because of its exploitation of a **SonicWall SSL-VPN** flaw. Figure 1 in the paper marks the timeline entry **“Feb 12. Unit42 Researchers observe Sonic Botnet.”** [2508.01909]

Within the paper’s taxonomy, Sonic is not presented as a wholly novel malware family, but as a **Mirai variant** that preserves Mirai-like propagation characteristics while updating its exploit surface toward newer enterprise, networking, and IoT targets [2508.01909]. This positioning is important. The article repeatedly frames Sonic as a member of a lineage whose distinguishing properties are automated scanning, propagation, compromise of Internet-exposed devices, and deployment of Mirai-derived binaries. Sonic’s distinctiveness is therefore not its basic architecture, but its exploit portfolio and recency.

The paper emphasizes that Sonic is notable for **multiple recent and unknown vulnerabilities**, rather than for a documented Sonic-specific bot population or a quantified operational campaign. This matters interpretively: the evidence base for Sonic in the paper is strongest on compromise mechanics and post-exploitation tooling, but comparatively weak on command-and-control telemetry and botnet-scale measurement [2508.01909].

## 2. Exploit surface and targeted vulnerabilities

The Sonic section and Table III associate the variant with a heterogeneous set of vulnerabilities affecting security appliances, network-attached storage, device-management software, routers, switches, and embedded firmware [2508.01909]. The paper presents this exploit set as distinct from those of Satori, Mukashi, and Moobot.

| Target | Identifier | Weakness or access condition |
|---|---|---|
| SonicWall SSL-VPN | N/A | “VPN Exploit”; unauthenticated remote code execution via old Bash vulnerable to ShellShock |
| D-Link DNS-320 Revision Ax | CVE-2020-25506 | OS command injection |
| Yealink Device Management 3.6.0.20 | CVE-2021-27561 | Command injection |
| Arm Trusted Firmware-M through 1.2 | CVE-2021-27562 | Out-of-bounds write |
| Micro Focus Operation Bridge Reporter 10.40 | CVE-2021-22502 | Code injection |
| Netis WF2419 | CVE-2019-19356 | OS command injection / authenticated RCE |
| NETGEAR JGS516PE | CVE-2020-26919 | Lack of access control at the function level |
| Unspecified products | Unknown | Three unidentified command-injection vulnerabilities |

The vulnerability most closely tied to the botnet’s naming is the **VisualDoor SonicWall Secure Socket Layer VPN Command Injection** affecting **SonicWall SSL-VPN**, exposed through **`/cgi-bin/jarrewrite.sh`**. The text describes this as **unauthenticated remote code execution** via an old Bash version vulnerable to **ShellShock**, with command execution as the **“nobody”** user [2508.01909].

The D-Link path centers on **CVE-2020-25506** in **D-Link DNS-320 Revision Ax**, specifically **`system_mgr.cgi`**, where arbitrary command execution is attributed to improper sanitization of HTTP parameters, notably **`f_ntp_server`**. The Yealink path uses **CVE-2021-27561**, associated with **`/sm/api/v1/firewall/zone/services`**, and is described as allowing command execution **as root** **without requiring any authentication**. The Micro Focus path uses **CVE-2021-22502**, tied to improper sanitization of the **username** parameter in the **`LogonResource`** endpoint, yielding **remote code execution**. The Netis path uses **CVE-2019-19356** through the **tracert diagnostic tool** in the router web management page, with **authenticated** command execution **as root**. The Netgear path uses **CVE-2020-26919**, which the paper characterizes as enabling **unauthenticated attackers** to execute arbitrary code through missing function-level access control. The Arm case, **CVE-2021-27562**, is included in Sonic’s targeted set, but the paper explicitly does **not** explain how the botnet operationalizes that bug during propagation [2508.01909].

A further complication is the paper’s assertion that Sonic also uses **three unknown vulnerabilities**, all described only as some type of **command injection**. No CVEs, product names, packet traces, or exploit strings are supplied for these. This lack of specificity is one reason Sonic is presented as technically concerning yet still somewhat opaque [2508.01909].

## 3. Infection chain and propagation workflow

Although the paper does not provide a Sonic-exclusive sequence diagram, it describes a compromise chain that combines Mirai’s baseline propagation model with Sonic-specific exploitation and downloader stages [2508.01909]. The workflow begins with Internet-facing target acquisition. The paper states that Mirai variants, including Sonic, exhibit **scanning and propagation**, and generalizes in its conclusion that these variants **pseudorandomly search for open ports** and **use brute-force attacks with common usernames and passwords**. For Sonic specifically, the presence of **Zmap** and an SSH brute forcer in its post-exploitation toolkit supports automated large-scale discovery and credential attacks [2508.01909].

Exploitation terminates in command execution sufficient to invoke a downloader. The paper explicitly states that **upon successful exploitation**, Sonic uses **`wget`** to download a malicious shell script [2508.01909]. The exploit surfaces named in the text are web-management, VPN, or management-API endpoints, and in the Netis case an authenticated administrative diagnostic interface. For some paths, the paper provides exact endpoints or parameters, but it does **not** provide raw exploit syntax or HTTP request bodies.

After the initial exploit, the botnet downloads shell-scripted staging components. The paper identifies **`lolol.sh`** and **`install.sh`** as concrete artifacts, along with **`nbrute`** and **`combo.txt`** [2508.01909]. The staging scripts then execute several Mirai binaries one by one. These binaries are described as “dark binaries” based on the Mirai codebase and stored under the filename **`nginx`** for evasion.

The propagation logic is dual-track. Sonic is both an exploit-driven worm and a credential-abuse botnet. According to the paper, the dark binaries propagate either through the named exploits or through **brute-forced SSH connections using hard-coded credentials**. The file **`combo.txt`** contains commonly used credentials, while **`nbrute`** uses that file to brute-force SSH connections with IP addresses. The script **`install.sh`** downloads **GoLang v1.9.4**, the Go standard **SSH** package, and **Zmap** [2508.01909].

This attack model differs in emphasis from classic Mirai as summarized in the same paper. Original Mirai is described there primarily as abusing **Telnet** on ports **23/2323**, whereas Sonic is characterized by a mixture of **web and VPN RCE/command injection exploitation** and **SSH brute forcing** [2508.01909]. That shift broadens the accessible victim class from consumer IoT devices to a wider management-plane attack surface.

## 4. Host modification, concealment, and attempted persistence

The paper attributes several post-exploitation functions specifically to **`lolol.sh`** [2508.01909]. It is said to delete key folders on the compromised host that are responsible for **scheduling jobs** and **starting up processes**. It downloads the Mirai-derived dark binaries, saves them under the name **`nginx`**, and implements **packet filters** that block incoming traffic on commonly used **SSH, HTTP, Telnet, and similar ports**.

These behaviors imply a takeover strategy oriented toward interference as much as persistence. Blocking common management ports can impede administrator access and may also reduce competition from other malware families. Naming the binary **`nginx`** suggests a basic masquerading tactic, using a common process or file name to blend into expected system contents. The deletion or tampering of scheduling- and startup-related folders suggests an attempt to alter local execution conditions beyond mere transient compromise [2508.01909].

Persistence, however, is presented cautiously. The paper states that **`lolol.sh`** is “supposed to be rerun every hour,” but also reports that **“the cron command-line utility is said to be improperly configured”** [2508.01909]. The implication is not robust persistence, but rather an attempted **cron-based persistence mechanism** whose correctness is doubtful. This is one of the few concrete operational limitations attributed to Sonic in the paper.

The combination of packet filtering, downloader staging, masqueraded binary placement, and partial persistence makes Sonic resemble a lightweight operational platform rather than a single-shot exploit script. Yet the paper does not present artifact hashes, filesystem forensics, or process-lifecycle telemetry in sufficient detail to elevate those observations into a complete implant model [2508.01909].

## 5. Command-and-control, capabilities, and evidentiary limits

Sonic is described as a **Mirai variant**, so its inclusion in a **C&C-controlled botnet** lineage is explicit at the family level [2508.01909]. The downloaded binaries are based on the **Mirai codebase**, and the scripts are clearly designed to spread malware and operationalize the botnet. Beyond that, the paper is notably sparse on Sonic-specific command-and-control telemetry. It provides **no Sonic-specific C2 IP addresses**, **no Sonic-specific TCP/UDP C2 ports**, **no protocol message formats**, and no command taxonomy comparable to the much richer C2 treatment given for Mukashi [2508.01909].

This evidentiary asymmetry is important for avoiding overstatement. The paper supports the existence of a Mirai-style control plane by family resemblance, but not a concrete reconstruction of Sonic’s C2 infrastructure. Likewise, the botnet’s objectives are clearest in terms of **infection and propagation**, not a documented Sonic-only attack catalog. The paper states that, as a Mirai variant, Sonic sits in a family used for **DDoS attacks**, but it does **not** present a measured Sonic-specific DDoS campaign, volumetric event, or operational trace [2508.01909].

A similar limitation applies to scale. The article provides no exact **Sonic bot count**, no **infection-speed metric**, no **regional distribution**, no **scanning volume**, and no **success-rate estimate** [2508.01909]. It does provide quantitative context for other variants—such as Satori’s early growth and Moobot’s DDoS reporting—but those figures are explicitly not Sonic-specific. The technical significance assigned to Sonic therefore derives from breadth of attack surface, downloader-based propagation, SSH credential abuse, and use of unidentified vulnerabilities, rather than from a measured prevalence claim.

This evidentiary profile can lead to a common misunderstanding: that Sonic is important because its scale has been directly quantified. The paper supports the opposite conclusion. Sonic is important in the article because it is **exploit-rich** and **recency-heavy**, while its operational size remains underdescribed [2508.01909].

## 6. Defensive implications and analytical interpretation

The paper’s defense discussion is framed at the Mirai-family level, but several recommendations map directly onto Sonic’s attack paths [2508.01909]. The most immediate is **patch and update management** for exposed devices and services, since Sonic targets known vulnerabilities in **SonicWall SSL-VPN, D-Link DNS-320, Yealink Device Management, Arm Trusted Firmware-M, Micro Focus Operation Bridge Reporter, Netis WF2419, and NETGEAR JGS516PE**. The article recommends **periodically updating firmware and applications** and, more generally, designing devices for **automatic firmware/OS updates**.

A second direct implication concerns **input validation**. Several Sonic-linked exploits are explicitly described as arising from **improper sanitization** or injection flaws, including the D-Link **`f_ntp_server`** parameter, the Micro Focus **username** parameter, and the Yealink command-injection endpoint. The paper therefore recommends **proper constraint validation**, since many of the relevant vulnerabilities arise from **injection attacks** [2508.01909].

A third implication concerns **credential hygiene**. Sonic uses **brute-forced SSH connections using hard-coded credentials**, with **`combo.txt`** storing common usernames and passwords and **`nbrute`** applying them against target IPs. The paper recommends changing default credentials, adopting more complex and unique credentials, and having manufacturers **randomize usernames and passwords** [2508.01909].

Exposure management is also central. Although the paper’s generic examples emphasize Telnet ports **23/2323**, the same logic extends directly to Sonic’s web-management, SSH, and SSL-VPN surfaces. The article recommends securing networks with **VPNs**, a **separate network**, and **firewall/IDS/IPS** deployments, as well as **closing/stopping nonessential services** and leaving devices offline if not used for long periods [2508.01909]. A plausible implication is that limiting Internet exposure of administrative CGI endpoints, router/switch web management, device-management APIs, and SSH materially reduces Sonic’s reachable attack surface.

Finally, the paper notes that botnets often have difficulty maintaining control once an infected device is **rebooted**, especially if the underlying vulnerability is then patched [2508.01909]. In Sonic’s case, this observation is especially pertinent because the paper describes its cron-style rerun mechanism as improperly configured. This suggests that Sonic’s persistence may be brittle on at least some targets, though the paper does not convert that into a universal remediation guarantee.

Taken together, Sonic1 emerges as an exploit-oriented Mirai variant whose analytic significance lies in compromise methodology rather than fully disclosed operations. It is best understood as a Mirai-style propagation engine updated for newer enterprise, networking, and IoT attack surfaces, with a workflow centered on web/VPN exploitation, shell-scripted payload delivery, SSH brute force, and Mirai-derived binary deployment [2508.01909]. The article’s strongest conclusion is therefore not that Sonic’s scale has been measured, but that a contemporary Mirai descendant can combine known high-severity flaws, unknown command injections, and lightweight post-exploitation tooling into a broad, adaptable infection platform.

Source: https://www.emergentmind.com/topics/sonic1