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Malware Analysis Writeup: effie.png

Author: Taylor Christian Newsome
Date: 2026-03-21
Analysis Environment: Debian (clumsy)

1. Target File

Property Value
File Name effie.png
SHA256 e6a03dbc9ac6ea0f6f4303d4591184db330543d84c72f52f410fcb1109d0ef51
Source https://efchat.net/src/assets/effie.png
Acquisition wget https://efchat.net/src/assets/effie.png

2. Initial Observations

The file was retrieved with a Content-Type: text/html header despite its .png extension. A quick static analysis confirmed the file is not a valid PNG image but an HTML document.

2.1 MIME Type Mismatch

$ file -b --mime-type effie.png
text/html

The file extension implies an image, but the actual content is HTML. This mismatch is a common technique to bypass naive file-type filters or to deceive users into executing a web page disguised as an image.

2.2 File Size and Structure

  • Size: 2374 bytes
  • First bytes: <!doctype html> (hexdump confirms no PNG magic bytes)

3. Static Analysis

3.1 File Header and Hexdump

The first 4096 bytes consist entirely of an HTML document. No PNG signature (89 50 4E 47) is present.

$ hexdump -C effie.png | head
00000000  3c 21 64 6f 63 74 79 70  65 20 68 74 6d 6c 3e 0a  |<!doctype html>.|
00000010  3c 68 74 6d 6c 20 6c 61  6e 67 3d 22 65 6e 22 3e  |<html lang="en">|
...

3.2 Strings Analysis

Strings output reveals a complete HTML document with:

  • Meta tags (viewport, theme-color, Open Graph, Twitter Card)
  • Embedded JSON-LD (Schema.org)
  • Multiple <script> tags loading remote JavaScript resources
  • A <div id="root"> container (typical for React/Vue applications)

3.3 Extracted URLs

The following external URLs were identified:

  • https://challenges.cloudflare.com/turnstile/v0/api.js?render=explicit
  • https://efchat.net
  • https://efchat.net/src/assets/effie.png
  • https://platform.twitter.com/widgets.js
  • https://schema.org

The presence of Cloudflare Turnstile (a CAPTCHA service) and Twitter widgets suggests the page is designed for interactive use, potentially to lure users into a legitimate-looking chat interface.

3.4 Binwalk Output

Binwalk confirmed the presence of HTML headers and footers:

DECIMAL       HEXADECIMAL     DESCRIPTION
--------------------------------------------------------------------------------
16            0x10            HTML document header
2366          0x93E           HTML document footer

No other embedded files were detected.

4. Suspicious Characteristics

  • File Extension Masquerade: The .png extension is misleading; the file is actually an HTML document.
  • Remote Script Inclusion: Scripts from challenges.cloudflare.com and platform.twitter.com are loaded, which could introduce third‑party tracking or additional malicious payloads.
  • Potential for Phishing: The page mimics a chat platform (efchat.net) and could be used to steal credentials or deliver malware through social engineering.
  • No Actual Image Data: The file contains zero PNG image data, reinforcing the masquerade.

5. Conclusion

effie.png is not an image file; it is an HTML document that poses as a PNG. This type of masquerade is often used in phishing campaigns or web‑based malware delivery to bypass security controls that rely solely on file extensions. The file’s structure and external dependencies indicate it is likely part of a larger web application (possibly a legitimate one), but its deceptive extension warrants caution.

Threat Level: Medium – The file itself is not inherently malicious, but its deceptive nature and the potential for interaction in a browser environment create risk.

6. Recommendations

  1. Do Not Open with Image Viewers – Treat the file as HTML, not an image. Avoid opening it in a default browser without sandboxing.

  2. Investigate Server‑Side Endpoints – The domain efchat.net and its assets should be examined for malicious content or compromise. The fact that the server returns HTML for a .png URL is suspicious.

  3. Network Traffic Analysis – If this file was encountered in an environment, review network logs for any calls to the embedded URLs, especially after the file was accessed.

  4. Update Security Policies – Implement MIME‑type validation based on content (not just extension) in security tools and email gateways.

  5. Sandbox Analysis – If further analysis is required, open the file in an isolated browser (e.g., using a sandbox or a disposable VM) to observe its behavior.

7. Appendix: Analysis Commands and Output

Below is a summary of the commands used during analysis (executed on a Debian system).

# Download
wget https://efchat.net/src/assets/effie.png

# Hash and MIME check
sha256sum effie.png
file -b --mime-type effie.png

# Examine header
head -c 4096 effie.png

# Extract strings and filter suspicious patterns
strings -a -n 8 effie.png | grep -Ei '<script|<html|iframe|javascript:|eval\(|base64,|data:text/html|application/javascript|window\.location|document\.|onerror=|onclick=|https?://'

# Hexdump
hexdump -C effie.png

# Binwalk
binwalk effie.png

# Full strings
strings effie.png

All commands confirmed the file is an HTML document with no image data.

Analysis completed by Taylor Christian Newsome