Malicious PDF — malware analysis report

Static analysis result for SHA-256 8c35ef50b265befa…

MALICIOUS

PDF

94.9 KB Created: 2021-09-01 13:28:08 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-31
MD5: 0f1672de8f4e1519d87ffd81fd4e7ee2 SHA-1: 51de93a1fb60708782f7ecfa2fac64e98178bf4d SHA-256: 8c35ef50b265befa695bc2043fbad745e9e30a7a03454233947a6358538e0a58
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with many embedded URLs pointing to potentially compromised WordPress upload directories and other disposable hosting. The document body is heavily obfuscated and unreadable, suggesting it is not intended for direct user interaction but rather to host malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9965

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://lnianemarzenie.pl/userfiles/file/bolekurepafudoxotini.pdf In PDF document text
    • http://kaufdeinauto.de/wp-content/plugins/formcraft/file-upload/server/content/files/16094867daaec4---ranogesojurijepuw.pdfIn PDF document text
    • http://cck-brno.cz/ckfinder/userfiles/files/59647506522.pdfIn PDF document text
    • http://www.kindytennis.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bc5bed247e0---7634325714.pdfIn PDF document text
    • http://terremeraude.com/userfiles/file/73007102698.pdfIn PDF document text
    • http://atlonnuri.org/UpLoadImage/editer/files/71665576139.pdfIn PDF document text
    • http://unnatiwelfareorganization.com/ckfinder/userfiles/files/vefawirixuridoluzomiwun.pdfIn PDF document text
    • https://apoc.com.au/wp-content/plugins/super-forms/uploads/php/files/8847756c5727e80926fd2d65742fee9f/mapisi.pdfIn PDF document text
    • http://furniture83.com/upload/files/11596635497.pdfIn PDF document text
    • https://vestol.bg/files/file/jenutidavu.pdfIn PDF document text
    • https://arzhosting.com/calisma2/files/uploads/worixopoxozofevirefeta.pdfIn PDF document text
    • http://pebyte.com/wp-content/plugins/super-forms/uploads/php/files/i27034204ovjcr82k14ii0r781/44851803685.pdfIn PDF document text
    • https://fidelishospice.com/ckfinder/userfiles/files/98975048220.pdfIn PDF document text
    • https://sayurhijau.com/contents/files/vumurabimival.pdfIn PDF document text
    • https://luyenthitoeic.info/userfiles/file/76515784552.pdfIn PDF document text
    • http://ever0036.com/assets/uploads/ckedit/files/20210603002632.pdfIn PDF document text
    • https://www.alertgy.com/wp-content/plugins/super-forms/uploads/php/files/875cb67e557c0e8c035f1d781b9136bc/seravatozavufinawekikeg.pdfIn PDF document text
    • https://carthink.org/wp-content/plugins/formcraft/file-upload/server/content/files/160982e7d54f91---32589406997.pdfIn PDF document text
    • https://valleyrestoration.net/home/apf/public_html/ckfinder/userfiles/files/87820399131.pdfIn PDF document text
    • http://le-lemniscus-incandescent.fr/ckeditor/upload/files/rozotigadoz.pdfIn PDF document text
    • http://thicongdiennuocmiennam.com/uploads/files/49723679406.pdfIn PDF document text
    • http://krindustria.com.br/site/wp-content/plugins/formcraft/file-upload/server/content/files/16094636484f6e---xozexejogoxurup.pdfIn PDF document text
    • https://armandofalconi.net/userfiles/file/4641025589.pdfIn PDF document text
    • http://urdu-hadith.com/survey/userfiles/files/dimanejitozejemusila.pdfIn PDF document text
    • http://meble-tk.pl/userfiles/file/karavunidufufinujef.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/DOqCt-cVA4I/uplcv?utm_term=waygate+inspection+academyPDF 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_off00010ad5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10AD5 10820 bytes
SHA-256: 31df02e90fe252505bcbf9e9c91ee70fe99b567625a2ee7284804ab9f73ff423
font_01_sfnt_off000123a0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x123A0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00013bb2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13BB2 18884 bytes
SHA-256: 6f9f5b2606a9f26771e14436a207cbf315111c64281c291c94f21390d908c7e9