Malware

icmpShell

For your environment

Hunt this family in your stack

Mallory pivots from this family to the IOCs, detections, and named campaigns that touch your stack, and pages you when something new lands.

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MITRE ATT&CK

Techniques & procedures

13 distinct techniques documented for this family, organized by ATT&CK tactic.

Execution

1 technique

T1059.004Unix ShellEvidence2

MITRE ATT&CK Matrix Mapping Tactic: Execution T1059.004: Unix Shell Implementation details: Hijacks a pseudo-terminal (PTY) utilizing fork() and dup2().

Persistence

1 technique

T1205Traffic SignalingEvidence1

Tactic: Persistence T1205: Traffic Signaling Implementation details: Employs magic bytes and flags like 0xFFFFFFFF as wake-up triggers.

Stealth

5 techniques

T1027Obfuscated Files or InformationEvidence1

T1027: Obfuscated Files Information Implementation details: Stack strings for passwords and paths prevent static extraction.

T1036.004Masquerade Task or ServiceEvidence1

T1036.004: Masquerading Implementation details: Alters process arguments to mimic benign daemons like qmgr.

T1070.003Clear Command HistoryEvidence1

T1070.003: Clear History Implementation details: Injects HISTFILE=/dev/null into environment variables.

T1205Traffic SignalingEvidence1

Tactic: Persistence T1205: Traffic Signaling Implementation details: Employs magic bytes and flags like 0xFFFFFFFF as wake-up triggers.

T1564Hide ArtifactsEvidence1

T1564: Hide Artifacts Implementation details: Uses AF_PACKET sniffing to remain invisible to local netstat/ss.

Command and Control

8 techniques

T1001Data ObfuscationEvidence2

T1001: Data Obfuscation Implementation details: icmpShell hides its tracking mechanisms directly inside the network layer headers. By truncating the Linux Process ID (PID) and injecting it into the 16-bit ICMP Identifier field, and hardcoding the ICMP Sequence Number to 1234, it obfuscates its session tracking data as standard network metadata.

T1071Application Layer ProtocolEvidence1

Most critical of the novel BPFDoor versions are httpShell, which prioritizes C2 concealment within HTTP traffic to allow BPF logic to view for certain magic markers in inner packets, and icmpShell, which creates an interactive shell to impede static firewall rules while also supporting bidirectional ICMP tunnels, RC4 encryption, and UDP/ICMP hole-punching

T1090ProxyEvidence2

T1090: Proxy Implementation details: Uses ICMP relay to bounce traffic through internal segments.

T1095Non-Application Layer ProtocolEvidence3

icmpShell, which creates an interactive shell to impede static firewall rules while also supporting bidirectional ICMP tunnels, RC4 encryption, and UDP/ICMP hole-punching

T1205Traffic SignalingEvidence1

Tactic: Persistence T1205: Traffic Signaling Implementation details: Employs magic bytes and flags like 0xFFFFFFFF as wake-up triggers.

T1572Protocol TunnelingEvidence3

icmpShell, which creates an interactive shell to impede static firewall rules while also supporting bidirectional ICMP tunnels, RC4 encryption, and UDP/ICMP hole-punching

T1573Encrypted ChannelEvidence1

icmpShell, which creates an interactive shell to impede static firewall rules while also supporting bidirectional ICMP tunnels, RC4 encryption, and UDP/ICMP hole-punching

T1573.001Symmetric CryptographyEvidence2

T1573.001: Symmetric Cryptography Implementation details: e.g. Enforces the X: plaintext tag and encrypts the underlying PTY output via an RC4 cipher (using the hardcoded ICMP key).

ACTIVITY FEED

Recent activity

1 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

1 SOURCESView more in app

rapid7 blogNews

Apr 2, 2026

New Whitepaper: Stealthy BPFDoor Variants are a Needle That Looks Like Hay

An ICMP-based shell/backdoor variant that uses magic ICMP packets for activation, RC4-encrypts victim responses with a hardcoded key, supports ICMP relay/tunneling, uses heartbeat hole-punching to keep firewall state active, and terminates after 12 seconds of inactivity for stealth.

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets match these IOCs, which detections are missing, which campaigns to expect next, and what to do in the next 30 minutes.

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IOC matching

Match every observed IP, domain, and hash against your live telemetry.

Threat actor attribution

Named campaigns wielding this family, with evidence pinned to each claim.

Exploited vulnerabilities

CVEs this family uses for access and lateral movement.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

MITRE ATT&CK mapping13

Every documented technique, ranked by evidence weight.

Researcher chatter

Reddit, Mastodon, and CTI community discussion around this family.

Back to malware

Malware

icmpShell

For your environment

Hunt this family in your stack

Mallory pivots from this family to the IOCs, detections, and named campaigns that touch your stack, and pages you when something new lands.

Start free trial

MITRE ATT&CK

Techniques & procedures

13 distinct techniques documented for this family, organized by ATT&CK tactic.

Execution

1 technique

T1059.004Unix ShellEvidence2

MITRE ATT&CK Matrix Mapping Tactic: Execution T1059.004: Unix Shell Implementation details: Hijacks a pseudo-terminal (PTY) utilizing fork() and dup2().

Persistence

1 technique

T1205Traffic SignalingEvidence1

Tactic: Persistence T1205: Traffic Signaling Implementation details: Employs magic bytes and flags like 0xFFFFFFFF as wake-up triggers.

Stealth

5 techniques

T1027Obfuscated Files or InformationEvidence1

T1027: Obfuscated Files Information Implementation details: Stack strings for passwords and paths prevent static extraction.

T1036.004Masquerade Task or ServiceEvidence1

T1036.004: Masquerading Implementation details: Alters process arguments to mimic benign daemons like qmgr.

T1070.003Clear Command HistoryEvidence1

T1070.003: Clear History Implementation details: Injects HISTFILE=/dev/null into environment variables.

T1205Traffic SignalingEvidence1

Tactic: Persistence T1205: Traffic Signaling Implementation details: Employs magic bytes and flags like 0xFFFFFFFF as wake-up triggers.

T1564Hide ArtifactsEvidence1

T1564: Hide Artifacts Implementation details: Uses AF_PACKET sniffing to remain invisible to local netstat/ss.

Command and Control

8 techniques

T1001Data ObfuscationEvidence2

T1071Application Layer ProtocolEvidence1

T1090ProxyEvidence2

T1090: Proxy Implementation details: Uses ICMP relay to bounce traffic through internal segments.

T1095Non-Application Layer ProtocolEvidence3

icmpShell, which creates an interactive shell to impede static firewall rules while also supporting bidirectional ICMP tunnels, RC4 encryption, and UDP/ICMP hole-punching

T1205Traffic SignalingEvidence1

Tactic: Persistence T1205: Traffic Signaling Implementation details: Employs magic bytes and flags like 0xFFFFFFFF as wake-up triggers.

T1572Protocol TunnelingEvidence3

icmpShell, which creates an interactive shell to impede static firewall rules while also supporting bidirectional ICMP tunnels, RC4 encryption, and UDP/ICMP hole-punching

T1573Encrypted ChannelEvidence1

icmpShell, which creates an interactive shell to impede static firewall rules while also supporting bidirectional ICMP tunnels, RC4 encryption, and UDP/ICMP hole-punching

T1573.001Symmetric CryptographyEvidence2

T1573.001: Symmetric Cryptography Implementation details: e.g. Enforces the X: plaintext tag and encrypts the underlying PTY output via an RC4 cipher (using the hardcoded ICMP key).

ACTIVITY FEED

Recent activity

1 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

1 SOURCESView more in app

rapid7 blogNews

Apr 2, 2026

New Whitepaper: Stealthy BPFDoor Variants are a Needle That Looks Like Hay

What this page doesn’t show

The version that knows your environment.

Start free trial

IOC matching

Match every observed IP, domain, and hash against your live telemetry.

Threat actor attribution

Named campaigns wielding this family, with evidence pinned to each claim.

Exploited vulnerabilities

CVEs this family uses for access and lateral movement.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

MITRE ATT&CK mapping13

Every documented technique, ranked by evidence weight.

Researcher chatter

Reddit, Mastodon, and CTI community discussion around this family.