Malicious PDF — malware analysis report

Static analysis result for SHA-256 a91cb3ccf16ffd94…

MALICIOUS

PDF

78.3 KB Created: 2021-03-17 03:04:32 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-27
MD5: fd2cf506c8d378c49d2e994b11a4a909 SHA-1: c993db54aacdb4773108f3f3545171d230d265b2 SHA-256: a91cb3ccf16ffd9462e2a89fe214f45868f69deb625c1a72b17d071fd4e902b1
66 Risk Score
Tags
free-cdn-ebook-manual-lure

Malware Insights

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

The PDF file contains numerous embedded URLs, many of which point to disposable domains and are flagged as part of a link farm. The ML classifier strongly indicates maliciousness. The document body, though heavily obfuscated, suggests a lure related to a 'worksheet', and the presence of external URIs indicates an attempt to redirect the user to a potentially malicious site for further exploitation.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 4

  • 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://xajibur.ru/123?utm_term=bce+and+ce+worksheet PDF link annotation
    • https://cdn.sqhk.co/wujodazera/hejihac/91917027585.pdfIn PDF document text
    • http://sopidemeleket.mygamesonline.org/muximoxuwig.pdfIn PDF document text
    • http://dapajurop.mygamesonline.org/what_is_the_next_dog_man_book_called.pdfIn PDF document text
    • https://cdn.sqhk.co/dawezizupata/UIQjeif/81098664691.pdfIn PDF document text
    • http://jawunefuda.mygamesonline.org/lemisiwezilafixo.pdfIn PDF document text
    • http://tranquils.space/guwatopepumoronudabikijazjp73f.pdfIn PDF document text
    • http://wozekozexufoxol.scienceontheweb.net/59763442369.pdfIn PDF document text
    • http://zaxevef.getenjoyment.net/kinovitimazo.pdfIn PDF document text
    • http://health2health.online/71850325902ua635.pdfIn PDF document text
    • http://bibopasaxuvibu.mypressonline.com/48803387354.pdfIn PDF document text
    • http://larebalin.mypressonline.com/what_is_nh22co.pdfIn PDF document text
    • http://lonotel.mygamesonline.org/viwerapekajo.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://uploads.strikinglycdn.com/files/4d678ddb-1380-43a1-9939-190363ec7a86/gogijigovo.pdfIn PDF document text
    • http://juborekif.atwebpages.com/nyc_economic_development_corporation_salary.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/f335a92b-a12e-4a3d-8d02-a7912be838ee/global_warming_map_skills_worksheet_answer_key.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/ce816179-7a19-4944-9333-235aa834b330/vobonovovinipemezogazo.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/b7682a48-5096-41d4-a95c-dde553aecabd/how_to_get_a_proofreading_job_online.pdfIn PDF document text
    • http://tavamikilav.myartsonline.com/what_do_you_need_to_check_when_buying_a_second_hand_car.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/c00bfbdc-4afd-4970-b01b-b38bbaf1127c/how_to_calculate_force_in_magnetic_field.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/e0ec27e3-3bfc-41e3-92f6-1e183c8a2058/what_does_son_of_man_mean_in_hebrew.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/acd24698-787b-4819-8db2-f45344215005/ruloxadukerem.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_off0000f394.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF394 5200 bytes
SHA-256: 3a30ffd653acb8d67856245bde169a6dcd7359cedae92e665ea96858bd3961bc
font_01_sfnt_off00010556.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10556 11468 bytes
SHA-256: 367ab49a4b806c35335a7da6f7702ca28abc44c99ff3e69222a00be8f19b5b8d

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