Malicious PDF — malware analysis report

Static analysis result for SHA-256 8d4c14bb13d36a7b…

MALICIOUS

PDF

82.6 KB Created: 2021-09-17 15:49:55 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: a01d45e44383aea6c5dc9d1d7cb2e694 SHA-1: 81edbafac16e157e1b0df41b8d2b9dcf4bfafba6 SHA-256: 8d4c14bb13d36a7b45b15f2189f62ebeb2512d0931808296188abc5c2fc10df7
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF file was detected as malicious by ML classifiers and ClamAV, indicating a phishing or malware distribution attempt. It functions as a link farm, containing numerous URLs that point to compromised WordPress upload directories and other disposable hosting, likely to distribute further payloads or conduct phishing. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather as a container for malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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://synerhu.ru/uplcv?utm_term=best+write+my+paper PDF link annotation
    • https://www.diktu.com/wp-content/plugins/formcraft/file-upload/server/content/files/161346151176d5---pajujubezusimozesiramike.pdfIn PDF document text
    • http://suportti.com/wp-content/plugins/formcraft/file-upload/server/content/files/16139dbaec18fb---41860414452.pdfIn PDF document text
    • http://friluftsgruppen.se/wp-content/plugins/formcraft/file-upload/server/content/files/161383c8d27eb8---felijukaxutelemujoburon.pdfIn PDF document text
    • http://formpart.com/upload/ckfinder/files/62496713992.pdfIn PDF document text
    • http://yugang360.com/upload_fck/file/2021-9-16/20210916022503743464.pdfIn PDF document text
    • https://www.unicodesystems.com/wp-content/plugins/super-forms/uploads/php/files/r1md6d2die43h4im7qfq6llum3/53744250095.pdfIn PDF document text
    • https://lean-ds.com/upload/editor/file/ravisigemufe.pdfIn PDF document text
    • http://zhizhencn.com/filespath/files/20210912100944.pdfIn PDF document text
    • https://tatsolarlight.com/uploads/files/kumovolivuvapamu.pdfIn PDF document text
    • http://manu-transport.com/documents/file/77505013256.pdfIn PDF document text
    • https://genegurumiraclehealer.com/userfiles/file/vubekenafef.pdfIn PDF document text
    • https://biocoils.com/img/file/79309170277.pdfIn PDF document text
    • http://isspskola.lv/userfiles/files/56748200539.pdfIn PDF document text
    • http://phutungquanghieu.com/app/webroot/files/ckfinder/files/5340406618.pdfIn PDF document text
    • http://feminella.ro/upload/fck/3339700055.pdfIn PDF document text
    • http://studiocinti.eu/userfiles/files/loxufodefanoboke.pdfIn PDF document text
    • http://tubesealer.com/uploaded/file/357150669613a5ac4f0eea.pdfIn PDF document text
    • http://graphicon.hu/wp-content/plugins/formcraft/file-upload/server/content/files/1613563082c98e---50051783952.pdfIn PDF document text
    • https://chinese-wall.tw/upload/files/92278537648.pdfIn PDF document text
    • https://rtvpuls.com/ckfinder/userfiles/files/putumixubofema.pdfIn PDF document text
    • http://studiomarazzi.eu/userfiles/files/kukuwesuxuvorukigiraw.pdfIn PDF document text
    • http://korea-labels.com/ckfinder/userfiles/files/tiferekuvexitelekirafobux.pdfIn PDF document text
    • http://impex-italia.it/userfiles/files/80224831442.pdfIn PDF document text
    • http://sattosushi.com/uploads/files/suvonekisuka.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_off0000e04f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE04F 10396 bytes
SHA-256: abaafa0fee0b460137f193b31960f8cd369003519d1ee7fbacda1bdfff913328
font_01_sfnt_off0000f7f7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF7F7 17252 bytes
SHA-256: 6bedb9aafcd1982361e19127a2377de6867f535362f6ce78c15904fdc6a11702
font_02_sfnt_off000124ce.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x124CE 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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