Malicious PDF — malware analysis report

Static analysis result for SHA-256 4bf1636485c3de3b…

MALICIOUS

PDF

87.5 KB Created: 2021-07-13 20:35:12 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 69f1054528ba96b998f689323e200b8d SHA-1: e33addfac6e018b7fd4fe44a4242ca9ffb7ae444 SHA-256: 4bf1636485c3de3b783260ddf576af3ff5d5f89bbce63d1bab0476f992029270
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

This PDF file was identified as malicious by ML classifiers and ClamAV, indicating it is likely a phishing or malware distribution lure. The heuristics reveal it functions as a link farm, with numerous URLs pointing to compromised WordPress sites and disposable domains, suggesting an attempt to redirect users to malicious content. The document body is heavily obfuscated and appears to contain metadata from the wkhtmltopdf tool rather than user-readable content, reinforcing its role as a container for malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9948

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
  • 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 http://tubietelbar.hu/uploadfile/32320369806.pdf In PDF document text
    • https://www.carlosfunes.es/wp-content/plugins/formcraft/file-upload/server/content/files/160db0d0f1b72a---56742895619.pdfIn PDF document text
    • https://www.golddustdental.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ab231d5ee89---vovazapunekulidufemoleme.pdfIn PDF document text
    • http://rollfactorytogo.com/uploads/files/buwazesisorivesoxok.pdfIn PDF document text
    • http://bamt.be/wp-content/plugins/formcraft/file-upload/server/content/files/16087b81334966---pomufezegidugunivol.pdfIn PDF document text
    • http://pokorny-podlahy.cz/UserFiles/File/79929952841.pdfIn PDF document text
    • http://totalfinance.ca/wp-content/plugins/formcraft/file-upload/server/content/files/1608ebef9b9585---86485400412.pdfIn PDF document text
    • http://www.stratcareerservices.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608d180cadd7d---gilelep.pdfIn PDF document text
    • http://churchliferesources.org/wp-content/plugins/formcraft/file-upload/server/content/files/160c953f077d7f---bugoruwavitibakidafarat.pdfIn PDF document text
    • http://adoriantarla.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160760d2d0e09c---21613894817.pdfIn PDF document text
    • https://belgradenightlife.info/wp-content/plugins/super-forms/uploads/php/files/bt2u32nmi5q8ge2akcic84eav3/vomujujewalasolotawi.pdfIn PDF document text
    • https://pelicanfinancialnetwork.com/ckfinder/userfiles/files/79761464885.pdfIn PDF document text
    • http://3handseg.com/wp-content/plugins/formcraft/file-upload/server/content/files/16081d4449b5e6---rutaj.pdfIn PDF document text
    • http://biemmecommerciale.eu/userfiles/files/62536216918.pdfIn PDF document text
    • http://petukmahaaaraj.com/userfiles/file/kiguvezifafojuxixamekivul.pdfIn PDF document text
    • https://art-lamps-rali.eu/files/file/4470254334.pdfIn PDF document text
    • https://costumeworld.com/wp-content/plugins/formcraft/file-upload/server/content/files/16093e32619084---wadoguj.pdfIn PDF document text
    • http://ciskmv.com/css/file/56277987723.pdfIn PDF document text
    • https://holocaustresearch.pl/nowy/photo/file/gumanavimuxuja.pdfIn PDF document text
    • http://www.julitolaschools.com/wp-content/plugins/formcraft/file-upload/server/content/files/16081e5766233d---dusufagajinuzar.pdfIn PDF document text
    • https://binarbaidrealestate.com/public_html/userfiles/file/25061354203.pdfIn PDF document text
    • https://evboosters.com/wp-content/plugins/super-forms/uploads/php/files/38031a18e8e056bee5d4208347835676/fumujimijamepag.pdfIn PDF document text
    • https://www.mclarenpress.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b307d3b9973---47051164843.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3vuEKuznOb8/uplcv?utm_term=fancy+word+for+importantPDF 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_off0000f271.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF271 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00010a88.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10A88 10612 bytes
SHA-256: 040e66e807e4f3bdea4b338306b352253bde3a1b1ee0c0b6f9627a962df10ffd
font_02_sfnt_off000122d4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x122D4 17932 bytes
SHA-256: 0ad345c72ea94d29c5233a9023d2b3e9d3c509671133f3323a099261dc9138ac

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