Malicious PDF — malware analysis report

Static analysis result for SHA-256 0b8d91d345b46261…

MALICIOUS

PDF

79.9 KB Created: 2021-04-28 23:14:23 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 9953d2846184840a4e62b62b37293f97 SHA-1: bd96bc7e79cccd31f6b6ce60d0f9af694e56f106 SHA-256: 0b8d91d345b462617467cece0a1743400cb35fefd6e5919c37580cf0ccec16bb
156 Risk Score

Malware Insights

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

The PDF contains a large number of external links, many of which are to other PDFs, suggesting a link farm or SEO spam campaign. The primary URL, 'https://druttle.ru/strik?utm_term=how+many+times+brighter+is+betelgeuse+than+the+sun', is likely part of this scheme. ClamAV and ML classifiers also flagged this PDF as malicious, specifically as a phishing trojan.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • 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
  • 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://druttle.ru/strik?utm_term=how+many+times+brighter+is+betelgeuse+than+the+sun
    • https://cdn-cms.f-static.net/uploads/4379371/normal_6030a4272a6d6.pdf
    • https://cdn-cms.f-static.net/uploads/4462345/normal_6009e555da4a4.pdf
    • https://static.s123-cdn-static.com/uploads/4490121/normal_5fff41e020dc2.pdf
    • https://static.s123-cdn-static.com/uploads/4419832/normal_5ff3ab44502e5.pdf
    • http://tesazidon.22web.org/how_to_adjust_the_draw_weight_on_a_compound_bow.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://bc732cde-fb09-4fee-8ab5-c82a45a1131b.filesusr.com/ugd/2ac701_a218d2eb36e94c388dbfaa6955ab4a69.pdf?index=true
    • https://s3.amazonaws.com/banula/36180036708.pdf
    • https://s3.amazonaws.com/nilititonawafim/eulogy_templates_for_brother.pdf
    • https://uploads.strikinglycdn.com/files/4cf5e839-0ff3-48a6-9822-55c3a7582e8c/toro_lx420_deck_belt_keeps_coming_off.pdf
    • https://uploads.strikinglycdn.com/files/a4b08dc2-9285-44f4-8903-cd5eefc90c31/divenegulawamisaka.pdf
    • https://s3.amazonaws.com/kuxuxemu/computer_science_questions_and_answers_for_interview.pdf
    • https://s3.amazonaws.com/wuwabobujasivor/what_are_the_6_latin_maxims.pdf
    • https://1cdd1dcb-54a5-4750-95ad-c4cce9a68cd1.filesusr.com/ugd/1e32c2_35438e90e1714ed3a84a1833ac6af170.pdf?index=true
    • https://uploads.strikinglycdn.com/files/8cb7589c-c7ff-4952-9845-02f62c732621/juloketuki.pdf
    • http://mizepapalatawu.rf.gd/pdf_file_download_for_android_mobile.pdf
    • https://uploads.strikinglycdn.com/files/847f233f-9d9d-4b45-9163-b73b3c46c66a/frm_level_1_practice_exam.pdf
    • https://uploads.strikinglycdn.com/files/96135ba0-21f7-43d1-bef4-5ce577f0835d/samsung_galaxy_s5_active_battery_ebay.pdf
    • https://uploads.strikinglycdn.com/files/35511b2d-70a1-433d-9887-6817e12e25bd/sizonenajetejow.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_off0000f9eb.bin
02f6806203d280fef365aaa4c1c33938f7a29fdd012b63b9b7db1a5de6d92a90		 pdf-font-stream PDF embedded font (sfnt) at offset 0xF9EB 5396 bytes
font_01_sfnt_off00010c2b.bin
a6e4292dec7e395147714b30142620eca5bb6dd9684e3526d9d8b06470a66ef4		 pdf-font-stream PDF embedded font (sfnt) at offset 0x10C2B 11012 bytes

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