Malicious PDF — malware analysis report

Static analysis result for SHA-256 837a4235080998ba…

MALICIOUS

PDF

79.2 KB Created: 2021-09-06 00:09:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 2c8f6b69f66cadf1f0b4cda4c9ba9cd1 SHA-1: 8aaab74ae781a3956ec055947a0a5ea223f4b4fd SHA-256: 837a4235080998bae389cddccf7388f98531285b121fb184882d2f0464b186bd
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was identified as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It contains numerous embedded links pointing to various websites, many of which appear to be compromised or disposable hosting, suggesting a link farm or phishing lure. The presence of PDF_SEO_DISPOSABLE_LINK_FARM and PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM heuristics further supports this, indicating the document is designed to drive traffic to potentially harmful sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9958

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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://huntic.ru/uplcv?utm_term=excel+vba+last+column+in+worksheet PDF link annotation
    • https://www.paparazzirestaurant.com.au/wp-content/plugins/super-forms/uploads/php/files/ad0271759fddf5fd588c6123268a447a/73230845054.pdfIn PDF document text
    • https://jnnjhansi.com/userfiles/file/21037570639.pdfIn PDF document text
    • https://licorne-hotel-restaurant.com/userfiles/file/vejivupomudixopemi.pdfIn PDF document text
    • http://daoltrading.com/userData/board/file/fabaja.pdfIn PDF document text
    • https://www.conkite.com/wp-content/plugins/super-forms/uploads/php/files/d6ebd4755ffefdcf2c1e8ded19e747b6/murujorobipogu.pdfIn PDF document text
    • http://hodori247.com/uploads/files/87472547702.pdfIn PDF document text
    • http://www.chp.pl/ckfinder/userfiles/files/66781640605.pdfIn PDF document text
    • http://safarang.com/basefile/files/zolipawulanumer.pdfIn PDF document text
    • http://myshopekerala.com/userfiles/file/zeneridijuzulavo.pdfIn PDF document text
    • http://deurenhanger.nl/userfiles/file/89427997991.pdfIn PDF document text
    • http://flemingfamilies.org/clients/8/8a/8af36a28baf44bfc7b8a7004fb4eaede/File/jiwigovekaniweguwifode.pdfIn PDF document text
    • https://estigotours.com/wp-content/plugins/super-forms/uploads/php/files/4c79096337c4ef1e3c529ead51f08725/zulezasupevifasetivurux.pdfIn PDF document text
    • http://www.trackls.com/application/ckeditor/ckfinder/userfiles/files/4911174255.pdfIn PDF document text
    • http://relocationservicesgroup.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606cb115bf69f---worogepiwugodoxutamim.pdfIn PDF document text
    • https://systematix.pl/userfiles/file/nujasetetifisu.pdfIn PDF document text
    • https://hotelangela.hu/userfiles/file/68312536442.pdfIn PDF document text
    • https://inchirieriavioane.ro/wp-content/plugins/formcraft/file-upload/server/content/files/161296639242f3---nalurabagaluwek.pdfIn PDF document text
    • https://yastudio.net/wp-content/plugins/super-forms/uploads/php/files/ab974623d0be26eac50eab31dc3ff85a/21009036042.pdfIn PDF document text
    • http://qiuyutv.com/userfiles/files/20210608113014.pdfIn PDF document text
    • https://mariapolis.net/ckfinder/userfiles/files/3105170896.pdfIn PDF document text
    • https://livres-d-art.com/ckfinder/userfiles/files/87661219376.pdfIn PDF document text
    • http://3colorjazz.com/fckeditor/userfiles/image/repamesevawa.pdfIn PDF document text
    • http://maksimetall.ru/files/nefunasorutosanozazev.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://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ceac.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCEAC 17600 bytes
SHA-256: 5a9e10bc06d023957b5f393991be680ac27d6c4b5b5a9eecbd7176591c5cd54d
font_01_sfnt_off0000fc2e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFC2E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011445.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11445 11064 bytes
SHA-256: 49a2dfce0ae0c62d863bc8009331a34777f6f83fcd804abdc984a96bc7736ec1

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