Malicious PDF — malware analysis report

Static analysis result for SHA-256 5391f1dd47d7ea6f…

MALICIOUS

PDF

72.3 KB Created: 2021-09-27 20:11:47 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 2c2717de73fc05802b59f477ad1acd86 SHA-1: e18ac6f756133ad569235d681d2de047296d932f SHA-256: 5391f1dd47d7ea6f871c950d7d9fec5b19be830e0a27c2c122865411a8419e87
126 Risk Score

Malware Insights

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

The PDF file was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs, many of which point to PDF files hosted on various domains, suggesting a link farm or redirection scheme. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' indicates a pattern of using disposable hosting for multiple distinct links, reinforcing the phishing lure. The document body is heavily obfuscated and unreadable, providing no direct content clues, but the overall structure and heuristic firings strongly suggest a phishing attempt to lure users to external sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9982

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://yongchengtech.com/uploads/files/202109161212118715.pdf In PDF document text
    • http://baovecongtruong.com/upload/files/ravavanaravakegusod.pdfIn PDF document text
    • http://klingende-zeder.de/wp-content/plugins/formcraft/file-upload/server/content/files/1614d09440773d---zinujegejozepopop.pdfIn PDF document text
    • http://tianfonmm.com/d/files/33718544947.pdfIn PDF document text
    • http://nutrizionisti.eu/public/thread/risorse/file/zadafegokuvap.pdfIn PDF document text
    • http://2017.letnifestiwal.pl/ckfinder/userfiles/files/mibatu.pdfIn PDF document text
    • https://what.whatproperty.ng/ckfinder/userfiles/files/88030037432.pdfIn PDF document text
    • http://kavtas.com/images_upload/files/tofulusugi.pdfIn PDF document text
    • http://pelejas.com/IMAGENS/CKFINDER/files/77229293842.pdfIn PDF document text
    • http://danieldesignpro.com/userfiles/mefizuvutuvutaxopuwiw.pdfIn PDF document text
    • https://casabresciani.it/uploads/file/56042213841.pdfIn PDF document text
    • http://bbfederico2.net/userfiles/file/72449809858.pdfIn PDF document text
    • http://esoftland.com/userfiles/file/keloxamogijisowuj.pdfIn PDF document text
    • https://theurbanthinktank.com/files/kusimotofej.pdfIn PDF document text
    • http://pscemetery.com/userfiles/file/39533915965.pdfIn PDF document text
    • http://edmo-cars.nl/images/file/sazuzewazi.pdfIn PDF document text
    • http://nemdanangpho.com/uploads/2021-09-19/images/files/fejiful.pdfIn PDF document text
    • http://kledingindex.nl/images/uploads/wagonatugu.pdfIn PDF document text
    • http://geofer.eu/userfiles/files/48656827640.pdfIn PDF document text
    • http://fujieshubao.com/zk/UploadFile/file/2021090718342873499.pdfIn PDF document text
    • http://wumag.pl/userfiles/file/90588464737.pdfIn PDF document text
    • https://tutorlookup.com/ckeditor/ckfinder/userfiles/files/75173175650.pdfIn PDF document text
    • http://copy-office.it/userfiles/file/18325820237.pdfIn PDF document text
    • http://araulmor.tel-cor.com/images/library/file/tedajowugexe.pdfIn PDF document text
    • http://i-physiology.ru/upload/52290225883.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3CAf4wW3hvY/uplcv?utm_term=istudiez+pro+androidPDF 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_off0000b440.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB440 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000cc52.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCC52 18272 bytes
SHA-256: 94992c2b24acae9ae235633e2aefe9338f03c9a29bc1bd9c41d95d893c7271db
font_02_sfnt_off0000fb5a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFB5A 10448 bytes
SHA-256: 4e59d827d72bf95affa8e524d4fc34115cc493a9584b570e202130a9201655fe