Malicious PDF — malware analysis report

Static analysis result for SHA-256 41257e40b4f83603…

MALICIOUS

PDF

65.9 KB Created: 2021-10-03 05:00:21 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 817e54f13e5e193fc66138dfe71dc826 SHA-1: f3eafa55f0c779d362cfb6934d352b927e15be7d SHA-256: 41257e40b4f83603dfd0c4247d2c2c5a0b88bc72972c8d541de334b48a9d8757
184 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains embedded JavaScript and is identified as a phishing lure by multiple heuristics, including an image-only document with an action trigger. It also functions as a link farm, directing users to multiple compromised CMS upload locations, indicating an attempt to host malicious content or redirect to phishing sites. The ML classifier and ClamAV detection strongly support its malicious nature.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9994

Heuristics 8

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • Image-only document with action trigger (screenshot lure) medium PDF_IMAGE_LURE
    PDF has 1 image(s), only 0 text block(s), carries a click-outward action, and is only 65 KB — typical shape of a phishing lure where a full-page screenshot hides a clickable button that launches or submits to an attacker URL.
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL https://alcc.vn/wp-content/plugins/super-forms/uploads/php/files/i0hf5gg22kng6utr0fk0mdu2ac/6684155320.pdf In PDF document text
    • http://studiorumeo.it/userfiles/files/desibimavawazijizola.pdfIn PDF document text
    • http://preprod.app-nomads.com/ugecam/admin/ckfinder/userfiles/files/fiserelareviwodexaxawekig.pdfIn PDF document text
    • https://kes-stv.ru/wp-content/plugins/super-forms/uploads/php/files/cb7d85ade27ebf41f83da2b80e8c0b00/77320975888.pdfIn PDF document text
    • https://luxurybaths.marblobaths.ph/app/webroot/img/files/70989212252.pdfIn PDF document text
    • https://mma-montessori.com/admin/ckfinder/userfiles/files/rarobiferisasog.pdfIn PDF document text
    • http://www.rosabrockenhaus.ch/ckfinder/userfiles/files/fipow.pdfIn PDF document text
    • https://independentmusicleague.com/wp-content/plugins/super-forms/uploads/php/files/b6e6c88b7b775637e0dbf2040b82318f/94559325532.pdfIn PDF document text
    • https://accessnepal.org/userfiles/file/tepikovakalegezatodajubi.pdfIn PDF document text
    • https://triatlonshop.cz/userfiles/file/52479124889.pdfIn PDF document text
    • https://clubberia.com/js/ckfinder/userfiles/files/50281141612.pdfIn PDF document text
    • http://studiotecnicoligioni.com/userfiles/files/83173676019.pdfIn PDF document text
    • https://himalayanwanderer.com/himalayan/userfiles/files/5445846242.pdfIn PDF document text
    • https://bongkartuantakur.com/contents/files/jizifuwajegizulexi.pdfIn PDF document text
    • http://ntouioc.ntou.edu.tw/ckfinder/userfiles/files/71616419289.pdfIn PDF document text
    • http://www.parinet.fi/tiedostot/files/jidumibositobo.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/fzgW7-mxBc0/uplcv?utm_term=amy+winehouse+song+meaningsPDF link annotation
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000a71c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xA71C 10592 bytes
SHA-256: 6ce1affd5183c1227b74231d12e33e233625362f0ae7ee2f2de58d24b2d69f25
font_01_sfnt_off0000bf2e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBF2E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000d740.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD740 14344 bytes
SHA-256: 772275a68bf1afafec044f3066e0e246e8b41fe66ba6e8a660c209f416ec7f6a