Malicious PDF — malware analysis report

Static analysis result for SHA-256 9840f39f5b449db9…

MALICIOUS

PDF

115.6 KB Created: 2021-09-04 16:44:30 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 4a6ccd65fb8a9c4e56bfe5fc2e0215a3 SHA-1: 5f1fb395fc382999738281f781529b3def16ed35 SHA-256: 9840f39f5b449db93c50004c021f9b6b4d3b468765f8d90289ca33d7eacb3eab
156 Risk Score

Malware Insights

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

The PDF contains numerous links pointing to compromised WordPress sites and other disposable hosting, indicating it functions as a link farm. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for SEO poisoning or phishing campaigns. The file's structure and numerous external links are consistent with a malicious document designed to redirect users to potentially harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9889

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://xpressup.com/userfiles/file/56662239744.pdf
    • http://www.blackhillsdancecentre.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d1f9f325aaf---givanorizubowodenalojobu.pdf
    • http://www.altrus.pl/wp-content/plugins/formcraft/file-upload/server/content/files/160b1e38f5a967---55107972015.pdf
    • http://mopi.eu/ckfinder/userfiles/files/xoretemawufetazoba.pdf
    • http://www.immiflex.com/wp-content/plugins/formcraft/file-upload/server/content/files/16113d4e89eb75---gubedinijigixu.pdf
    • https://trade.inter-ural.ru/ckfinder/userfiles/files/kapiwe.pdf
    • https://digireg.ch/upload/3625436758.pdf
    • https://christembassyromford.org/wp-content/plugins/super-forms/uploads/php/files/d7cac9ff606a131958d269d2eab615c9/6087443466.pdf
    • http://www.corazondelsol.es/ckfinder/userfiles/files/pivagux.pdf
    • https://pametnidom.hr/pametne_kuce/userfiles/file/25249768466.pdf
    • http://all-pass.com/folder/editor/file/pubefokinu.pdf
    • http://bukharageorgia.com/sites/default/files/file/8723550793.pdf
    • http://palyavalaszto.hu/teszt/upload/file/4148867608.pdf
    • https://staffxrecruitment.com/wp-content/plugins/super-forms/uploads/php/files/b4b0fecc761ce9ba38e693c53e1c292a/tukodasibuvil.pdf
    • http://zs-oilfieldequip.ru/d/files/sovivuwujidalatatene.pdf
    • http://www.gametimecatering.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b9c0bce25f2---tunavapu.pdf
    • http://quickfix-poland.com/wp-content/plugins/formcraft/file-upload/server/content/files/16090166330719---fevitonivegeduxal.pdf
    • https://senzedigicraft.com/wp-content/plugins/super-forms/uploads/php/files/6b35e7398c65530aea44569cdb45102d/netaxekovusox.pdf
    • http://mko-yug.ru/wp-content/plugins/super-forms/uploads/php/files/90b6bc423b5d3d24b475e65cebbbc175/9754830264.pdf
    • https://nstyapi.com/resimler/files/19250410484.pdf
    • http://jungvassar.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/sosuxifuwomizawosawe.pdf
    • http://hosteleriayvending.com/ckfinder/userfiles/files/54689645443.pdf
    • http://gma.ge/admin/ckeditor/ckfinder/userfiles/files/rosijoxonujatazelesapu.pdf
    • http://culbertsonlawyer.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/vojaxisunaxewap.pdf
    • https://yuktiedu.com/wp-content/plugins/super-forms/uploads/php/files/0d919f9d41a2b4dd095941b9f85a7ebf/57511307363.pdf
    • http://alexlunacoach.com/img/editor/file/patasirik.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3vuEKuznOb8/uplcv?utm_term=avian+anatomy+atlas+pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00015e2e.bin
36dd68a01bfd8296f702192a5af2ff7232109b2174b2746f9a6dc4e85f780776
pdf-font-stream PDF embedded font (sfnt) at offset 0x15E2E 10588 bytes
font_01_sfnt_off00017663.bin
1caf5df071e0e7681fdbef0a56c4e4356d39c36030c805d548c81198b157e07c
pdf-font-stream PDF embedded font (sfnt) at offset 0x17663 19032 bytes
font_02_sfnt_off0001a850.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x1A850 16792 bytes