Malicious PDF — malware analysis report

Static analysis result for SHA-256 7fdd0664d581a06b…

MALICIOUS

PDF

87.8 KB Created: 2021-09-10 16:03:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: e9280fb4d85d5cd9776dab974bff76ca SHA-1: e6b1a1cbcb4bd2914c786726715f8fca70ed1e98 SHA-256: 7fdd0664d581a06bf8447cb14923f298fd43d2b07404213efbf95c032b457656
156 Risk Score

Malware Insights

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

The file is identified as malicious by ML classifiers and ClamAV, specifically as a phishing trojan. Static analysis reveals it functions as a link farm, containing numerous URLs pointing to other PDF files hosted on various domains, some of which appear to be compromised CMS uploads. This suggests a multi-stage attack where the initial PDF serves as a lure to download further malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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://atek-ent.com/upload/file/pogamokema.pdf In PDF document text
    • http://hwayoung.kr/upfile/files/37348650512.pdfIn PDF document text
    • http://15449010.com/FileData/ckfinder/files/20210905_07791F8E7CD41C2A.pdfIn PDF document text
    • https://oxi-dental.ro/imagini_ws/86839079926.pdfIn PDF document text
    • http://ayurvedicclinic.org/userfiles/file/wogimatumobinawexa.pdfIn PDF document text
    • http://tecs4.com/intranet/ckfinder/userfiles/files/zapupojuxafewuki.pdfIn PDF document text
    • http://www.chinahkcarplate.com/wp-content/plugins/formcraft/file-upload/server/content/files/161365dae6da33---65174967376.pdfIn PDF document text
    • https://ferest.ro/imagini_ws/fizedubotiriweniwodowir.pdfIn PDF document text
    • http://www.barankayalar.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/161307ceea9fd4---48236291378.pdfIn PDF document text
    • http://smenergy.kr/uploaded/file/2102023902612fa67ac9516.pdfIn PDF document text
    • http://tradotel-riviera.com/file/daredotimajani.pdfIn PDF document text
    • http://sklepjola.pl/userfiles/file/luramog.pdfIn PDF document text
    • https://skiclubraonbaccarat.fr/pdf/donomiwonalaxew.pdfIn PDF document text
    • https://www.gsccn.it/wp-content/plugins/formcraft/file-upload/server/content/files/161317ef95f8de---fufewi.pdfIn PDF document text
    • http://zjnep.com/ckeditor/ckfinder/userfiles/files/kevimowi.pdfIn PDF document text
    • https://nezrenweb.com/calisma2/files/uploads/23733104108.pdfIn PDF document text
    • http://bon-mar.com/fck_user_files/file/53747232648.pdfIn PDF document text
    • http://dlabiura.kbo.pl/ckfinder/userfiles/files/54193521212.pdfIn PDF document text
    • https://lorenzonimmigrationlaw.com/wp-content/plugins/formcraft/file-upload/server/content/files/161379dca873f2---watufewuzusatu.pdfIn PDF document text
    • https://unicon-msk.ru/data/files/fixivisadosu.pdfIn PDF document text
    • http://salamino.pl/userfiles/file/rawegerukoxe.pdfIn PDF document text
    • https://vildmarksjagt.dk/userfiles/file/28677710568.pdfIn PDF document text
    • https://paardenwelzijnscheck.nl/app/webroot/files/ckeditor_files/files/kagofamaduto.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/BkSY9tpko7c/uplcv?utm_term=abs+material+advantages+and+disadvantagesPDF 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_off0000f513.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF513 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00010d2a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10D2A 10660 bytes
SHA-256: 45075c476223e0fe2eb2f57a0f9b71a2d16fa2e19ee24d3dbe35c268fbd06715
font_02_sfnt_off00012562.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12562 16912 bytes
SHA-256: b9aed8784aa5c1d5228258c028ad9b973e504da32de6d036b928002d8abdf29f