Linux Netcat Execution with -e/-c Launching Common Shells

Alerts on Linux executions of nc/ncat using -e that reference common shells, indicating potential reverse-shell setup.

FreeReviewedSigma · High · v4

Product: linux
Category: process_creation
Author: @d4ns4n_, Nasreddine Bencherchali (Nextron Systems) (SigmaHQ), DRL 1.1
Published: 2023-04-07
Updated: 2026-09-24

ATT&CK techniques

Execution

Recon
Resource Dev
Initial Access
Execution
- T1059Command and Scripting Interpreter
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule identifies Linux process executions where a netcat binary (including common nc/ncat paths and variants) is invoked with command-line flags -e or -c and followed by typical shell interpreters. Attackers often use this pattern to spawn a shell over the network, enabling interactive remote access. The detection relies on process creation telemetry with the executable image name and the full command-line content to match the netcat variant, the -e/-c flags, and common shell paths or names.

Reporting behind it

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Linux Netcat Execution with -e/-c Launching Common Shells

Pivot detection · T1059 · 9 related

Changelog

v4
Candidate ingested via manual entry.2026-09-24
v2
Candidate ingested via manual entry.2026-07-31
v1
No changelog recorded for this version.2026-07-30

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

linux-process-execution-of-netcat-ncat-with-e-followed-by-shell-invocation-7f734ed0

title: Linux Netcat Execution with -e/-c Launching Common Shells
id: 7be6f4b1-88be-417b-a4ad-cf2a5448cf0f
status: test
description: This rule identifies Linux process executions where a netcat binary (including common nc/ncat paths and variants) is invoked with command-line flags -e or -c and followed by typical shell interpreters. Attackers often use this pattern to spawn a shell over the network, enabling interactive remote access. The detection relies on process creation telemetry with the executable image name and the full command-line content to match the netcat variant, the -e/-c flags, and common shell paths or names.
references:
  - https://pentestmonkey.net/cheat-sheet/shells/reverse-shell-cheat-sheet
  - https://www.revshells.com/
  - https://www.hackingtutorials.org/networking/hacking-netcat-part-2-bind-reverse-shells/
  - https://www.infosecademy.com/netcat-reverse-shells/
  - https://man7.org/linux/man-pages/man1/ncat.1.html
  - https://github.com/SigmaHQ/sigma/blob/master/rules/linux/process_creation/proc_creation_lnx_netcat_reverse_shell.yml
author: "@d4ns4n_, Nasreddine Bencherchali (Nextron Systems), Huntrule Team"
date: 2023-04-07
modified: 2026-09-24
tags:
  - attack.execution
  - attack.t1059
logsource:
  category: process_creation
  product: linux
detection:
  selection_nc:
    Image|endswith:
      - /nc.openbsd
      - /nc.traditional
      - /nc
      - /ncat
      - /netcat.openbsd
      - /netcat.traditional
      - /netcat
  selection_flags:
    CommandLine|contains:
      - " -c "
      - " -e "
  selection_shell:
    CommandLine|contains:
      - " ash"
      - " bash"
      - " bsh"
      - " csh"
      - " ksh"
      - " pdksh"
      - " sh"
      - " tcsh"
      - /bin/ash
      - /bin/bash
      - /bin/bsh
      - /bin/csh
      - /bin/ksh
      - /bin/pdksh
      - /bin/sh
      - /bin/tcsh
      - /bin/zsh
      - $IFSash
      - $IFSbash
      - $IFSbsh
      - $IFScsh
      - $IFSksh
      - $IFSpdksh
      - $IFSsh
      - $IFStcsh
      - $IFSzsh
  condition: all of selection_*
falsepositives:
  - Unlikely
level: high
license: DRL-1.1
related:
  - id: 7f734ed0-4f47-46c0-837f-6ee62505abd9
    type: derived

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