Malicious PDF — malware analysis report

Static analysis result for SHA-256 31a5ec5fa91a86c6…

MALICIOUS

PDF

73.7 KB Created: 2021-09-13 19:52:20 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-29
MD5: a9f078e0beb68f5b29ce4700d57f76f6 SHA-1: 5e50a5209c0c497e6bfdd520c02f53a7c6ce104a SHA-256: 31a5ec5fa91a86c69608fe16af526f0dbb5624b2c9294e03a2c7dc3fb046b845
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by multiple heuristics, including a critical ClamAV detection and an ML classifier, indicating malicious intent. The heuristics identified it as a link farm with numerous external URIs pointing to potentially malicious PDF files, suggesting a distribution mechanism for further malware. While no scripts were explicitly extracted, the PDF structure and embedded links strongly suggest an attempt to redirect users to malicious content, likely for phishing or malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

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 http://kubablimel.pl/Image/files/xolilewobomu.pdf In PDF document text
    • http://ideatity.com/ckfinder/userfiles/files/jatulijiditifibewafunasov.pdfIn PDF document text
    • http://star-transform-moscow.ru/uimg/files/sidatulujixi.pdfIn PDF document text
    • https://hardlineconstruct.ro/app/webroot/files/userfiles/files/tipesogujufup.pdfIn PDF document text
    • http://baschin-heizung.de/meineBilderAlbertGrundschule/file/rezuveludetiranetotivaz.pdfIn PDF document text
    • https://voxel-avocats.fr/uploads/file/In PDF document text
    • http://moretonassets.net/userfiles/polefezogogexifozivoded.pdfIn PDF document text
    • https://soportedevida.mx/ckfinder/userfiles/files/sejuniwijeribevusenaritot.pdfIn PDF document text
    • https://my-natural-style.net/upload/files/kogumunalu.pdfIn PDF document text
    • http://dylogistics.com/userData/board/file/zosak.pdfIn PDF document text
    • http://brunagabriele.it/userfiles/files/rivuvawumezilili.pdfIn PDF document text
    • http://www.hgbehringer.de/img/files/files/tuzubebefapo.pdfIn PDF document text
    • http://riasztoszolnok.hu/admin/fck_upload/file/83196616478.pdfIn PDF document text
    • http://knowleangling.co.uk/ckfinder/userfiles/files/lamidirufawavi.pdfIn PDF document text
    • http://fijiembajak.com/uploads/ck_uploads/files/31301256742.pdfIn PDF document text
    • https://olterus.info/contents/files/wopazokatinukuvuruni.pdfIn PDF document text
    • http://ubytovani-budejovice.cz/picture/vtextu/file/sebagexadez.pdfIn PDF document text
    • http://dogalakustik.com/depo/sayfaresim/file/70995466942.pdfIn PDF document text
    • http://pensjonatagat.pl/userfiles/file/3474231089.pdfIn PDF document text
    • http://winhazel.com/indigo/ckfinder/userfiles/files/belikemoxodoxekivawovidu.pdfIn PDF document text
    • https://bimetoor.com/basefile/bimetoorir/files/69085095596.pdfIn PDF document text
    • http://www.aportecnica.com/imagenes/editor/file/30848377377.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/BkSY9tpko7c/uplcv?utm_term=physics+for+scientists+and+engineers+test+bank+pdfPDF link annotation
    • 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_off0000bcc4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBCC4 11200 bytes
SHA-256: f63b755100d0703d7523179a09ee1391d9c1d4f689ccf6d7407431cfc9e4ddf5
font_01_sfnt_off0000d687.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD687 16556 bytes
SHA-256: f37cfb88c9b92e4c15d4d909629bbcde77abfb726b9ddacf22b8c9f8f1f424d5
font_02_sfnt_off000100f0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x100F0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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