Malicious PDF — malware analysis report

Static analysis result for SHA-256 13c81e23bc0f3271…

MALICIOUS

PDF

81.7 KB Created: 2021-09-04 20:43:33 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 40ac3d611261aa11330e18ae35381334 SHA-1: 8a3618df3f982246392c1a74fb17387435f5d5c9 SHA-256: 13c81e23bc0f3271c19c4ebcf011f221844a14771b1a685a822e5890bcfd68c3
184 Risk Score

Malware Insights

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

This PDF document exhibits multiple indicators of malicious intent, including a high ML classifier score and ClamAV detection as a phishing trojan. The heuristics indicate it functions as a link farm, directing users to compromised WordPress sites and potentially disposable hosting, likely to facilitate phishing or malware distribution. The presence of a 'download button' lure and a callback lure further supports a scam or phishing attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

Heuristics 8

  • 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.
  • Callback phishing phone lure medium SE_CALLBACK_LURE
    Document asks the user to call a phone number in billing, refund, subscription, fraud, or security context — consistent with callback phishing or tech-support scam patterns. Suppressed for legitimate-issuer (IRS/gov/official-form) documents that carry no urgency or charge/dispute escalation.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://archism.ru/uplcv?utm_term=the+merchant+of+venice+pdf+download PDF link annotation
    • https://mosoptagro.ru/wp-content/plugins/super-forms/uploads/php/files/e244e93bf02c32584daee6b86284409e/38451533670.pdfIn PDF document text
    • https://assurancemauricie.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606f8eb411463---4963870182.pdfIn PDF document text
    • https://www.sussexweddingservices.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16070c7a79a377---notibijurunilubamogevage.pdfIn PDF document text
    • http://mouaumfb.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608c862d0604c---40978095124.pdfIn PDF document text
    • http://diegogenna.it/userfiles/files/96272873443.pdfIn PDF document text
    • http://kennyre.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608bc65f4dc3c---lefemo.pdfIn PDF document text
    • http://remobudostol.pl/pliki/garuvatidiga.pdfIn PDF document text
    • http://zadonskiy.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1609f6a53df136---15533489346.pdfIn PDF document text
    • https://www.bramfordgc.co.uk/ckfinder/userfiles/files/wujejujenimategurowijasin.pdfIn PDF document text
    • https://bikeid.net/ckfinder/userfiles/files/wujefuz.pdfIn PDF document text
    • http://ozona.pt/wysiwygfiles/file/pexidedixujawi.pdfIn PDF document text
    • https://www.gsccn.it/wp-content/plugins/formcraft/file-upload/server/content/files/1606c8a690d47f---vakafatibelugapaga.pdfIn PDF document text
    • https://gitedu.in/ckfinder/userfiles/files/67594571271.pdfIn PDF document text
    • https://soechi.id/userfiles/file/jusatezujotej.pdfIn PDF document text
    • http://viermaalh.nl/Bottesteyn/Site/afbeeldingen/file/1992498496.pdfIn PDF document text
    • http://hoondb.com/wp-content/plugins/formcraft/file-upload/server/content/files/16090acbf9654b---18378280646.pdfIn PDF document text
    • https://maloneslandscape.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606cad9bb8105---51581480221.pdfIn PDF document text
    • http://tecniagua.es/uploads/ckfinder/files/gopowusakopu.pdfIn PDF document text
    • https://holocaustresearch.pl/nowy/photo/file/49056491501.pdfIn PDF document text
    • https://www.ideaklinikkadikoy.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608d7878ee106---befanade.pdfIn PDF document text
    • http://mikomisushi.com/uploads/files/pakusukesos.pdfIn PDF document text
    • https://groupburuemas2.com/contents//files/walewalad.pdfIn PDF document text
    • http://alvasari.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608531d49c845---72433669894.pdfIn PDF document text
    • 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_off0000da51.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDA51 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f263.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF263 17992 bytes
SHA-256: 7970298d4cb1dd1d48af987984e786204d66157e3bbd5a17e038bafb96f0d93b
font_02_sfnt_off0001202e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1202E 10832 bytes
SHA-256: fc573781a17767840cbca38ba49adefd0a672342882de33ed93315a747a0ceaa

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