Delphinjector

Overview

Trojan:Win32/Delphinjector is a generic classification for malware or specialized droppers written in Delphi whose primary function is Process Injection (`T1055`). Delphi is popular among threat actors (like the authors of Emotet or early Ryuk variants) because it compiles into large, complex, standalone executables that are difficult to analyze statically and often bypass basic AV heuristics.

Understanding Delphinjector
To an end-user, the execution is invisible. For a SOC analyst, a Delphinjector detection is a major red flag indicating that a highly evasive staging mechanism has breached the endpoint. The Delphi binary is almost certainly a 'wrapper' designed to hollow out a legitimate process and inject a more destructive payload (like Cobalt Strike or ransomware) into memory.

Execution and Injection Mechanics
Upon execution, the Delphi executable typically drops a highly obfuscated payload into memory. It then launches a legitimate, trusted Windows process (like `svchost.exe`, `explorer.exe`, or `RegAsm.exe`) in a suspended state (`T1055.012`). It unmaps (hollows) the legitimate code from the suspended process's memory and injects its own malicious code. Finally, it resumes the thread. To the OS and many EDR tools, the executing code appears to be the legitimate Microsoft binary, completely bypassing application whitelisting and firewall rules.

Indicators of Compromise & Impact
The impact depends on the injected payload. Host-based IoCs require behavioral analysis (EDR). Analysts should look for a Delphi-compiled executable spawning legitimate Windows binaries (like `svchost.exe`) without the appropriate command-line arguments. Network IoCs involve that 'legitimate' process suddenly making outbound connections to low-reputation IP addresses. Memory forensics (dumping the `svchost.exe` process) is strictly required to extract the actual payload.

MITRE ATT&CK Techniques

Observed techniques used by this family, mapped to the MITRE ATT&CK framework:

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_DELPHINJECTOR {
    meta:
        description = "Detects Delphinjector (ransomware)"
        author = "SystemHelpdesk Boilerplate Generator"
        date = "2026-07-06"
    strings:
        $s1 = "delphinjector" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

Sigma Rule

title: Suspicious Delphinjector Activity
id: da64292b1b0b674837355fed425811e0
status: experimental
description: Detects generic indicators of the delphinjector malware family.
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
        CommandLine|contains:
            - "*delphinjector*"
    condition: selection
level: medium

Containment & Response Steps

Ordered checklist for responders. Adapt to your environment and engage professional support for active incidents.

1. Isolate the endpoint immediately; process injection is a precursor to severe attacks like ransomware or lateral movement.
2. Use EDR tools to identify the legitimate process that was hollowed out (e.g., `svchost.exe`) and terminate it.
3. Capture a live RAM dump of the infected host to allow forensic analysts to extract the injected payload from memory.
4. Investigate the initial execution of the Delphi executable (often a macro-enabled document or a downloaded crack).

What to Avoid

Common mistakes during response to this family that can destroy evidence, spread the infection, or worsen recovery.

1. Do not assume the machine is clean just because the initial Delphinjector executable was quarantined; the payload may already be running in memory.
2. Avoid whitelisting standard Windows binaries globally in your EDR, as this ignores process hollowing.

References & External Analysis

• Search "delphinjector" on VirusTotal (External Analysis)

Frequently Asked Questions

Related Families (Category: ransomware)

Explore other malware families in the same category:

• Titirez
• Wigon
• Systemhijack
• Dervec
• Kradword

Machine-readable

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