Shellcodef

Overview

Executive Summary

Infection Vector and Technical Capabilities

• Vulnerability Exploitation: The carrier file (e.g., a PDF) contains malformed data designed to trigger a specific vulnerability (like a Buffer Overflow or Use-After-Free) in the application parsing it.
• Execution Hijacking: When the vulnerability triggers, it corrupts the application's memory space, hijacking the execution flow and forcing the CPU to execute the embedded ShellcodeF block.
• The "Stager": Shellcode must be extremely small to fit within the exploit constraints. Therefore, it typically acts as a "stager." Its sole purpose is to connect back to the attacker's server, download a larger, more fully-featured secondary payload (like a RAT, Cobalt Strike beacon, or Ransomware loader), and execute it directly in memory.

Threat Assessment

Incident Response and Remediation

• Determine Exploit Success: The most crucial step is determining if the shellcode successfully executed or if it was blocked by EDR (e.g., blocked by Exploit Guard or ASLR/DEP). Analyze EDR telemetry for unexpected child processes spawning from applications like `winword.exe` or `AcroRd32.exe`.
• Vulnerability Patching: Identify the specific application that was targeted by the exploit and ensure it, and all related software, is immediately patched to the latest vendor specifications to close the vulnerability.
• Containment and Sweeps: If execution was successful, isolate the endpoint immediately. The shellcode likely downloaded a secondary backdoor. A deep forensic sweep is required to identify and eradicate the secondary payload.

Known aliases

Threat reports may refer to this family under multiple names:

• Exploit.Shellcode
• Trojan.ShellcodeF
• Win32/Exploit

MITRE ATT&CK Techniques

This family has been observed using the following ATT&CK techniques: T1203 T1059 T1055

Tactical Mitigations

Based on the techniques used by this family, consider the following defensive strategies:

• T1059: Restrict execution of scripting languages such as PowerShell, VBScript, or Python to authorized administrators. Enforce Script Block Logging.

Generated Detections (Boilerplate)

These YARA and Sigma rules are auto-generated based on the family name and aliases. They must be heavily tuned before deployment in a production environment.

YARA Rule

rule MALWARE_WIN_SHELLCODEF {
    meta:
        description = "Detects Shellcodef (ransomware)"
        author = "SystemHelpdesk Boilerplate Generator"
        date = "2026-07-06"
    strings:
        $s1 = "shellcodef" ascii wide nocase
        $s2 = "exploit.shellcode" ascii wide nocase
        $s3 = "trojan.shellcodef" ascii wide nocase
        $s4 = "win32/exploit" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

Sigma Rule

title: Suspicious Shellcodef Activity
id: a5637cf3c24812b16e16c029936d2866
status: experimental
description: Detects generic indicators of the shellcodef malware family.
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
        CommandLine|contains:
            - "*shellcodef*"
            - "*exploit.shellcode*"
            - "*trojan.shellcodef*"
            - "*win32/exploit*"
    condition: selection
level: medium

References & External Analysis

• Search "shellcodef" on VirusTotal (External Analysis)

Frequently Asked Questions

Related Families (Category: ransomware)

Explore other malware families in the same category:

• Winshow
• Serveradmin
• Mufanom
• Stocde
• Quireap

Machine-readable

Get this profile as JSON: https://jordanricky1604-ship-it.github.io/malware-families-catalog/api/shellcodef.json

Ecosystem & Interactive Environments

This profile is part of the Malware Families Catalog, a public dataset of 2,899 malware families. The catalog is also published across our ecosystem: Hugging Face, Kaggle, Zenodo, Replit, StackBlitz, CodeSandbox, and CodePen.