Malicious PDF — malware analysis report

Static analysis result for SHA-256 4a398e9179391b3b…

MALICIOUS

PDF

67.9 KB Created: 2021-09-09 06:47:43 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: f203c7d2b3b190152f13dc78ee9602db SHA-1: 30e87d1e16e09413eefbadfbeae28f304ed3946d SHA-256: 4a398e9179391b3bf815b99daca5fe973848b84e5d46332b989fa4a77a6c65a7
156 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. Heuristics indicate the document functions as a link farm, directing users to various disposable hosting sites, likely to download further malicious payloads. The presence of multiple PDF link farm indicators and a high ML score supports this assessment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9957

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 http://timnhanhonline.vn/upload/files/30195899501.pdf In PDF document text
    • https://webmenuplus.com/images/file/napoxawesulutad.pdfIn PDF document text
    • http://prmakeup.com/Image/files/nusefalivenagafage.pdfIn PDF document text
    • http://jockmurray.com/wp-content/plugins/formcraft/file-upload/server/content/files/161322d1c093f5---56779677209.pdfIn PDF document text
    • http://optimaglobal.net/ckupload/files/42093777256.pdfIn PDF document text
    • http://vetportonaccio.it/userfiles/files/82872097170.pdfIn PDF document text
    • http://apsons.eu/files/file/51197905328.pdfIn PDF document text
    • http://anhuifan.com/upload_fck/file/2021-9-2/20210902051915509731.pdfIn PDF document text
    • http://www.advokat.com/app/webroot/img/fck/file/39727990681.pdfIn PDF document text
    • http://nwhouse.ru/uploads/file/57820224218.pdfIn PDF document text
    • http://maschimaurizio.it/userfiles/files/24211417351.pdfIn PDF document text
    • http://rollfactorytogo.com/uploads/files/54559384906.pdfIn PDF document text
    • http://ccshecea.org/upload/files/gagawosijibarasa.pdfIn PDF document text
    • http://puntolinea.org/userfiles/files/folavo.pdfIn PDF document text
    • http://chinalabware.net/d/files/98421794658.pdfIn PDF document text
    • http://jiendurancecoaching.com/ckfinder/userfiles/files/nizovusulasodado.pdfIn PDF document text
    • http://allineers.morefriendship.com/upload/files/kopugofanijejaxu.pdfIn PDF document text
    • https://amezdigital.com/wp-content/plugins/super-forms/uploads/php/files/f885ed7a4d09edbb0cbf539e5567de03/69214581152.pdfIn PDF document text
    • http://icmasistemas.com/userfiles/files/kidujasolumoduju.pdfIn PDF document text
    • http://flamefitnessstudio.com/cewit/images/file/feridaxame.pdfIn PDF document text
    • https://ketdoanbus.com/webroot/img/files/balemipe.pdfIn PDF document text
    • https://ashasuchikala.com/ckfinder/userfiles/files/79519746567.pdfIn PDF document text
    • http://www.cargeacrew.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/161396f3250175---jumekolodosudurokekefe.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/LPIa9PGmDLg/uplcv?utm_term=root+installer+for+android+free+downloadPDF 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_off0000ae41.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xAE41 14540 bytes
SHA-256: 786da27baefaac9d5216a53e1f6dd30c8d59e629c6774457ae18599ade55f18f
font_01_sfnt_off0000d1fb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD1FB 10476 bytes
SHA-256: 8a2b28614b1f079289d0450b4e8532511b73de9458711dbb17f98163b388f6ab
font_02_sfnt_off0000e9fa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE9FA 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1