Malicious PDF — malware analysis report

Static analysis result for SHA-256 d81dc66b6d906670…

MALICIOUS

PDF

58.2 KB Created: 2020-11-23 06:13:47 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 5e532b10f58aecfd041c6478bb0f9c66 SHA-1: 1ceedad3de80125615a343200e171a4eb658221a SHA-256: d81dc66b6d9066703f3faf0f340367a8e1ebe457631bbc4560b7144d3639db3a
284 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The PDF contains a large number of links to external PDFs hosted on various disposable domains, indicating a link farm. One critical heuristic identified links to known malicious redirector infrastructure. Additionally, a high-severity heuristic flagged a social-engineering lure, instructing the user to install a browser extension or update, which is a common method for credential theft or malware delivery. The ML classifier also strongly indicated maliciousness.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

Heuristics 7

  • PDF links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • Browser extension / update installation lure high SE_BROWSER_INSTALL_LURE
    Document tells the user to install a browser extension, plugin, viewer, or browser update to view content — a common social-engineering path for credential theft and malware installation
  • 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.
  • 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://cctraff.ru/123?utm_term=madison+park+comforter+blue
    • https://gimifuzakid.weebly.com/uploads/1/3/4/3/134315082/sifiwewebaluduju.pdf
    • https://vafeperaj.weebly.com/uploads/1/3/4/5/134586379/0c659a5cbc.pdf
    • https://pefuxagofir.weebly.com/uploads/1/3/4/3/134359429/6d7de239e9d.pdf
    • https://cdn-cms.f-static.net/uploads/4374976/normal_5f8c164759b76.pdf
    • https://cdn-cms.f-static.net/uploads/4377678/normal_5f9f8c57ab4d3.pdf
    • https://gilolubirej.weebly.com/uploads/1/3/4/3/134309297/324129.pdf
    • https://digaporabanezaf.weebly.com/uploads/1/3/4/6/134689005/baraverud_finunoji_wugemekapoju_xojozodox.pdf
    • https://zonebudufekepok.weebly.com/uploads/1/3/4/3/134382159/bidutosetupeg.pdf
    • https://letolonenuxe.weebly.com/uploads/1/3/4/0/134095956/261161.pdf
    • https://pamixame.weebly.com/uploads/1/3/4/5/134589616/gowimunav.pdf
    • https://juximejejin.weebly.com/uploads/1/3/4/3/134365908/2ba5ca893a411.pdf
    • https://fodezamu.weebly.com/uploads/1/3/1/4/131407453/devuxupujikeninaferi.pdf
    • https://nigerizebamogut.weebly.com/uploads/1/3/4/5/134596745/furapewotux-nupavepozemeb.pdf
    • https://xexovelez.weebly.com/uploads/1/3/0/8/130813416/pupeden.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://uploads.strikinglycdn.com/files/a1e55529-6796-49c7-9f55-e7dd8796acbc/bapadorudogu.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://scripts.sil.org/OFL

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000a9fc.bin
6d7a6f94e167081aa57b9b4a4ae6ba01289699fd8cd386334a678a79b5df56f2		 pdf-font-stream PDF embedded font (sfnt) at offset 0xA9FC 5508 bytes
font_01_sfnt_off0000bcb2.bin
bcb3a9fce682edb2fcbe50409de364cb62ede6b0acf2d667ef4259ea2f58c07f		 pdf-font-stream PDF embedded font (sfnt) at offset 0xBCB2 9236 bytes

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