Malicious PDF — malware analysis report

Static analysis result for SHA-256 39dec9cd2fecfa1e…

MALICIOUS

PDF

73.8 KB Created: 2021-06-09 05:09:17 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-27
MD5: a13ce291b25072537dfa2d59d81ba129 SHA-1: 6cfc5d1872bee483d6311b47f1a9eef0c2229eab SHA-256: 39dec9cd2fecfa1ef3de05c7eab495d544d7aeaa001ea4fdd4e294d27b116e7a
126 Risk Score
Tags
free-cdn-ebook-manual-lure

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF file contains multiple external URIs, with one specifically pointing to 'https://archism.ru/pbw?utm_term=ubuntu+on+thumb+drive'. This URL, combined with the heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM', indicates a phishing attempt to lure users to a potentially malicious site. The ML classifier and ClamAV detection strongly support its malicious nature, classifying it as a phishing trojan.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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.
  • 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://archism.ru/pbw?utm_term=ubuntu+on+thumb+drive PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4384296/normal_60114587ae2b8.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4419832/normal_5ff92a84c7c96.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4490547/normal_6033fe0c10720.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4385436/normal_60290046d40de.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4421639/normal_601404db8cb99.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4490519/normal_5fcf455b2e8be.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4453102/normal_6046c1e7cff05.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4379722/normal_5ff2f4bcec194.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://sowenux.pbworks.com/f/58250557842.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/aa31219f-f427-444d-b2a5-e5423967c098/physics_for_railway_exam_in_hindi.pdfIn PDF document text
    • http://zanonot.pbworks.com/f/freealts_fortnite_account_generator.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/adb997d0-8a91-48f6-bcb5-3f825638a94e/beats_solo_2_wireless_headband_repair.pdfIn PDF document text
    • http://dejimebez.pbworks.com/w/file/fetch/144900816/baxobetobi.pdfIn PDF document text
    • http://jizakatum.pbworks.com/w/file/fetch/144498423/tesaxejifi.pdfIn PDF document text
    • http://lebunurivugu.pbworks.com/f/pert_math_practice_test_with_answers.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/ca75c37b-f3e2-47a6-81aa-45e920d0ee51/lg_l90_unlock_code_free.pdfIn PDF document text
    • http://tijigika.pbworks.com/f/how_to_fill_appraisal_form_in_bank.pdfIn PDF document text
    • 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e6ac.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE6AC 4836 bytes
SHA-256: 7bff909a170bbc3b4e482d4c067584380e4b83eff1426c72acb12392afbd1771
font_01_sfnt_off0000f6f6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF6F6 10408 bytes
SHA-256: 3016500769dc1b77233af68e62f574d209073248d58b4c5b2dca7d8bc130552d

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