Malicious PDF — malware analysis report

Static analysis result for SHA-256 4ba46b368cec02c0…

MALICIOUS

PDF

76.7 KB Created: 2021-09-12 12:21:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: a1b79f7b6e7e00857a7992dcd17401dc SHA-1: e7124ccd377fa68e51728f1e4b28936999720989 SHA-256: 4ba46b368cec02c074afaf8176448beb9855321b58196f27edca0bdeac55a20c
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many pointing to compromised CMS upload directories, suggesting it's part of a phishing or malware distribution scheme. The ML classifier and ClamAV detection strongly indicate malicious intent. The file's structure as a link farm on disposable hosting further supports its use in malicious campaigns.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

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://huntic.ru/uplcv?utm_term=stack+sort+puzzle
    • http://status.cz/UserFiles/File/89638339674.pdf
    • https://theshairpodcast.com/wp-content/plugins/super-forms/uploads/php/files/58c6c35230d57a106729d2de25e7b68b/17908590046.pdf
    • http://vietdubai.com/userfiles/file/13131514778.pdf
    • http://impressivetravelvietnam.com/upload/files/xixukevi.pdf
    • http://hellnocancershow.com/wp-content/plugins/formcraft/file-upload/server/content/files/161334118c29b2---75186546458.pdf
    • http://abwingssuffolk2.com/uploads/files/gitajefulorebenav.pdf
    • http://casier-a-bouteilles.com/file/nusevalinapetud.pdf
    • http://vizit-k.net/uploads/editor/files/supixanobuziri.pdf
    • http://p-jtech.com/userData/board/file/pixisejejezapaxazeduled.pdf
    • http://lg-palette.com/upload/files/12111002040.pdf
    • https://hasekei.jp/userfiles/file/76940781378.pdf
    • http://fskyok.com/uploadfile/files/77042526196.pdf
    • http://lnv-cnc.gr/userfiles/file/wuluz.pdf
    • http://vinhthuan.vn/upload/files/duvolupedajepubumudisak.pdf
    • http://samuiluxurytravel.com/Uploads/file/jowopowebojajatemipipux.pdf
    • https://stvorki.ru/files/file/kojovadutasilulixebiduxow.pdf
    • https://www.ezhealthcheck.com/wp-content/plugins/super-forms/uploads/php/files/5tbk0nrj3aklmaamji9m8rpo37/xojopetufirumunok.pdf
    • http://kanalizace-ul.cz/userfiles/file/14376440659.pdf
    • http://energy-labels.com/userfiles/file/gifabidavunerezetajekori.pdf
    • https://mgs-on-track.com/uploads/misc/files/noritegagoluvuvojanipufup.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_off0000c44b.bin
4595703d34be6368f6239d4c0b32e68b48f61711c95273c0b94b35b391d50d32		 pdf-font-stream PDF embedded font (sfnt) at offset 0xC44B 19220 bytes
font_01_sfnt_off0000f603.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1		 pdf-font-stream PDF embedded font (sfnt) at offset 0xF603 16792 bytes
font_02_sfnt_off00010e1a.bin
e0a9dd7392d9641d3169baef0fc0c13b660aa46fcda6884a0ff7b235dcb465ae		 pdf-font-stream PDF embedded font (sfnt) at offset 0x10E1A 10496 bytes

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