Malicious PDF — malware analysis report

Static analysis result for SHA-256 81bd5e474fc2f844…

MALICIOUS

PDF

86.6 KB Created: 2021-09-02 14:11:37 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: b0f08459f0557a1021dc3cea25584ba3 SHA-1: 2a92b65b4ea4b999250c3055fe4031a41072dd39 SHA-256: 81bd5e474fc2f844fbdf278a3ee3b2e02151ec7bb0d337e4375dab9346168b11
156 Risk Score

Malware Insights

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

This PDF file was identified as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. The heuristics reveal it functions as a link farm, with numerous embedded URLs pointing to compromised CMS uploads and disposable hosting, likely to distribute phishing content or malware. The presence of multiple external URIs and the 'PDF_SEO_DISPOSABLE_LINK_FARM' heuristic strongly suggest a campaign to lure unsuspecting users to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

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 https://philabc.ru/uplcv?utm_term=ehrlichiosis+canina+tratamiento+pdf PDF link annotation
    • https://www.femregenx.co.za/wp-content/plugins/super-forms/uploads/php/files/afk85jhttpkopal0kibe72jvbg/54918103838.pdfIn PDF document text
    • http://www.belladermeestetica.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1608b5323210f5---22565721771.pdfIn PDF document text
    • https://kolodezrus.ru/wp-content/plugins/super-forms/uploads/php/files/8fd2815869d2bea45db31381ae11a1f1/xizifuzaxiralikevojuniju.pdfIn PDF document text
    • http://www.heksan.com.pl/file/85663829167.pdfIn PDF document text
    • https://rowanmkt.com/Uploads/ckfinder/userfiles/files/wikenebewozasetonofosad.pdfIn PDF document text
    • http://ssujaxchapter.com/clients/83257/File/gizido.pdfIn PDF document text
    • http://abw10thstreetne.com/uploads/files/xopabopisusinafesukenil.pdfIn PDF document text
    • https://www.phoenixdentalacademy.co.uk/wp-content/plugins/super-forms/uploads/php/files/d687cf5ec169a55cde4c42b0863440a1/12706983550.pdfIn PDF document text
    • http://chanhbon.vn/media/ftp/file/xomolevikaloxupetofobiz.pdfIn PDF document text
    • http://srub-servis.ru/userfiles/file/vopinidowad.pdfIn PDF document text
    • https://dukra.sk/editor_uploads/files/59790512709.pdfIn PDF document text
    • https://bhsbeacon.com/FCKeditor/file/42184823154.pdfIn PDF document text
    • https://apoiotelecom.com/imagens/img_fckeditor/file/vubixutisumowe.pdfIn PDF document text
    • https://masterok-kovka.ru/wp-content/plugins/super-forms/uploads/php/files/8334a4eca12f01163bd64822ca396aab/nasogurenigobegaxumagola.pdfIn PDF document text
    • https://memoservicesrl.it/file/mulamavavasebalulelaxorem.pdfIn PDF document text
    • http://kondicionery-lubertsy.ru/upload_picture/file/39309122750.pdfIn PDF document text
    • https://iamluno.com/wp-content/plugins/formcraft/file-upload/server/content/files/16108cacd10059---35226273632.pdfIn PDF document text
    • http://sieuthivatlieuhoanthien.com/upload/files/lovutulurobalujoxoj.pdfIn PDF document text
    • http://tuzvedo.hu/elemek/file/6617707647.pdfIn PDF document text
    • https://ortechindustries.ca/ci/userfiles/files/gasofadetiwuxexa.pdfIn PDF document text
    • https://estidevelopers.com/wp-content/plugins/super-forms/uploads/php/files/f63cea90e0a7b081c6b5827eb4d6bbb6/wokatasowapowuniloponaz.pdfIn PDF document text
    • https://www.kunapak.com/wp-content/plugins/super-forms/uploads/php/files/573ndp5b7r982670lr49h5ht2r/79584770745.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_off0000eb33.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEB33 19112 bytes
SHA-256: 5e03173ca9cbf75c9493f5f1c4f883bebef0cdd2b2393170bde8c0901399dc77
font_01_sfnt_off00011bc4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11BC4 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000133db.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x133DB 10868 bytes
SHA-256: ab4170d656e1d0314b848bedea3fdf5e89d741c367e6712b09eb0fbe66247e82

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