Malicious PDF — malware analysis report

Static analysis result for SHA-256 b77dc4728bbb79f9…

MALICIOUS

PDF

77.7 KB Created: 2021-02-16 23:40:49 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-21
MD5: 50fd470770c2095907b4233ff74dad9c SHA-1: a2dbe1fc8c57a18e41ef658ddf5082ce35a4a922 SHA-256: b77dc4728bbb79f9df3242bba7560a7acaf198996fbc6298211639e0c270e0a8
186 Risk Score

Malware Insights

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

The PDF contains a large number of external links, many hosted on disposable domains, suggesting a link farm or phishing operation. The ML classifier and ClamAV detection strongly indicate malicious intent. The document body, though heavily obfuscated, appears to be an attempt to disguise the malicious links under a seemingly innocuous title.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • 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 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.
  • 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://druttle.ru/strik?utm_term=redwall+book+1 PDF link annotation
    • https://cdn.sqhk.co/rikopekela/qjbhhhj/33296728819.pdfIn PDF document text
    • http://carbags.site/sedona_method_workbook4ti9q.pdfIn PDF document text
    • https://cdn.sqhk.co/satidaruxami/Vih6Ij7/45317464445.pdfIn PDF document text
    • https://cdn.sqhk.co/vulovosovem/jbjezmC/7418692015.pdfIn PDF document text
    • https://cdn.sqhk.co/xokebuzizo/7UYBchh/reese_ball_hitch_grease.pdfIn PDF document text
    • https://cdn.sqhk.co/rijomawonuj/cRKhfRn/cats_crash_arena_turbo_stars_hack_mod_download.pdfIn PDF document text
    • https://cdn.sqhk.co/devuzemalut/ugghhij/57556780459.pdfIn PDF document text
    • https://nufapapezo.weebly.com/uploads/1/3/0/9/130969462/5782784.pdfIn PDF document text
    • http://my-favshopf.online/calfresh_application_spanishqyyc3.pdfIn PDF document text
    • http://osthondroz.com/makita_circular_saw_7_1_4_cordless5f8b0.pdfIn PDF document text
    • https://cdn.sqhk.co/movozuba/Rjeifhf/knives_crash_mod_apk_unlock_all.pdfIn PDF document text
    • http://erogan-encolumbia.site/evh_5150_iii_settingslkhes.pdfIn PDF document text
    • https://divetuguwopad.weebly.com/uploads/1/3/0/7/130739619/4292016.pdfIn PDF document text
    • https://cdn.sqhk.co/javijaxim/ajhjdha/bipiwutumiwe.pdfIn PDF document text
    • http://bigchance.pw/13105116682atvbf.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://lawakeweba.epizy.com/celebrate_me_home_the_perrys_sheet_music.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_off0000f509.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF509 4900 bytes
SHA-256: 7f18d9f1a953f821ae40cd39aff68e48b878770a80c9b846ef514396c6bd56bd
font_01_sfnt_off000105e4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x105E4 10508 bytes
SHA-256: 9f5028c770429e1723aaebab645a4830f04a1fb4b647799128d29ba82b55fb0e

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