Malicious PDF — malware analysis report

Static analysis result for SHA-256 027d26d34f22eb91…

MALICIOUS

PDF

75.2 KB Created: 2021-09-14 08:44:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 66fd201f09d7f9db71c8c50c40aaf166 SHA-1: d52d1a9da08e8e5c2c5eea40fc9c8c7dffb43c1c SHA-256: 027d26d34f22eb91f10a48b98851fafeb9009a53c5f1dda6cd2a32ab3f3d7e95
156 Risk Score

Malware Insights

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

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 numerous URLs pointing to other PDF files hosted on various domains, some of which appear to be compromised or disposable. This suggests a multi-stage attack where the initial PDF serves as a lure to download or access further malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9963

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 https://funbugs.ie/userfiles/file/41516818659.pdf In PDF document text
    • https://posaonakosovu.com/ckfinder/userfiles/files/1449589807.pdfIn PDF document text
    • http://bigcool.net/webroot/img/files/36794572533.pdfIn PDF document text
    • http://busangh.com/attfile/fckimg/file///2021090724558_849263729.pdfIn PDF document text
    • http://xn--xhq021fvrwdth.com/d/files/45732223638.pdfIn PDF document text
    • https://bokaichenyu.com/upload/files/vupinesulatoxunitajetero.pdfIn PDF document text
    • https://tennis-samara.ru/img/file/domimugogot.pdfIn PDF document text
    • https://shevtsov-art.com/uploads/files/78078312359.pdfIn PDF document text
    • http://arkystudio.eu/userfiles/files/retijubunoxigunowow.pdfIn PDF document text
    • http://claudiodauelsberg.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1613c3fc413526---zedinojozamak.pdfIn PDF document text
    • http://indyskischool.com/ckfinder/userfiles/files/99338997944.pdfIn PDF document text
    • https://www.espymetcalf.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613fdd92133ab---fosusaminodavixutufop.pdfIn PDF document text
    • https://quatden.vn/webroot/img/files/lumobuvafodiraduj.pdfIn PDF document text
    • https://juniorclublivorno.com/sitonews/images_upload/files/82881947008.pdfIn PDF document text
    • http://hostingureitings.lv/uploads/userfiles/files/85495418928.pdfIn PDF document text
    • http://ambvetesopo.eu/userfiles/files/60644271699.pdfIn PDF document text
    • http://biosite.ru/images/news/file/39633907590.pdfIn PDF document text
    • https://ms02bet.net/contents/files/lujegij.pdfIn PDF document text
    • http://massiimo.com/piceditor/file/mokaj.pdfIn PDF document text
    • https://hsse.hssanesteban.cl/files/85408559932.pdfIn PDF document text
    • http://custom-mugs-factory.com/uploadfile/files/38503886182.pdfIn PDF document text
    • https://ocvirapuato.com.mx/wp-content/plugins/super-forms/uploads/php/files/1d459a07b330af5d8485f262d92b2ede/40214660453.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/ngfLrbzwjls/uplcv?utm_term=top+50+smallest+country+in+the+worldPDF 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_off0000c25d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC25D 16564 bytes
SHA-256: a286a6d31ef369ae1fd8acb1dda56068f322cbf15bb79b37f7f53fa0fa4530e7
font_01_sfnt_off0000eca8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xECA8 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000104bf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x104BF 11300 bytes
SHA-256: d7977f6b33b00c6d2236b8b7709452d11a59892f9ba7b53116871cf3c206d714