Malicious PDF — malware analysis report

Static analysis result for SHA-256 f4ad8838c86a119b…

MALICIOUS

PDF

84.3 KB Created: 2021-09-21 08:17:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 7b95fee0b883d9766f3bd6b52cd355bb SHA-1: 23e306275b8ba57866f60c6f20aba6f4592d2a54 SHA-256: f4ad8838c86a119b41242b87c85d5907d7626668e865e9381b1d4b4c37c2169b
172 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains an embedded JavaScript stream and numerous external URIs, forming a link farm. Several heuristics indicate this is a malicious PDF, including a high-confidence ML classification and ClamAV detection. The link farm likely serves to redirect users to phishing sites or download further malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9912

Heuristics 8

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • Urgency / deadline lure low SE_URGENCY_LURE
    Document contains urgency or deadline language ('account will be terminated', 'action required within 24 hours', etc.) — useful context, but low-signal without other findings
  • 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://krisoc.ru/uplcv?utm_term=ram+booster+pro+apk+download PDF link annotation
    • http://pc75.net/upfiles/file/1630764047.pdfIn PDF document text
    • https://wyslijpaczki.pl/app/webroot/files/userfiles/file/10893886404.pdfIn PDF document text
    • http://goksirkrupskimlyn.pl/img/upload/files/39409459859.pdfIn PDF document text
    • http://truhlarstvi-strakonice.cz/files/file/79905859358.pdfIn PDF document text
    • http://www.auditsi.com/wp-content/plugins/formcraft/file-upload/server/content/files/16141b486d3d19---gidotoze.pdfIn PDF document text
    • http://connect-senior.ch/uploades/userfiles/file/xosumafexubopen.pdfIn PDF document text
    • https://basealimentare.it/webroot/files/fck_uploads/File/jebizetelawimoses.pdfIn PDF document text
    • https://gancza-yacht.pl/userfiles/file/vekumori.pdfIn PDF document text
    • https://innotek.vn/uploads/news_file/sutikike.pdfIn PDF document text
    • http://agama-rc.com/upload/files/borupujisop.pdfIn PDF document text
    • http://eprdel.cz/userfiles/file/zisisasaraf.pdfIn PDF document text
    • http://chipublichouse.com/ckfinder/userfiles/files/26548984992.pdfIn PDF document text
    • https://unitedcardsolutions.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613cfe355872f---sopodode.pdfIn PDF document text
    • http://studioboscono.it/userfiles/files/40129885634.pdfIn PDF document text
    • http://nfraccon.org/userfiles/file/23928784713.pdfIn PDF document text
    • https://jyapa.com/jhuoyue/uploadfiles/filalivazabofeguwomud.pdfIn PDF document text
    • https://www.partyshuttlebus.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/16141c6765a5d7---9626127035.pdfIn PDF document text
    • https://bitree.com/ckfinder/userfiles/files/xoduzopatakonusedena.pdfIn PDF document text
    • https://equinox-e.com/upload/files/65328196187.pdfIn PDF document text
    • http://abwingsbuffalo.com/uploads/files/zunasus.pdfIn PDF document text
    • http://cps-mbstu.edu.bd/app/webroot/js/ckfinder/userfiles/files/37702051532.pdfIn PDF document text
    • https://datatech-int.com/userfiles/file/81697860940.pdfIn PDF document text
    • https://eniedu.com/data/file/20210902050047.pdfIn PDF document text
    • https://beta.nhatthiengroup.com/files/uploaded/files/zabesazo.pdfIn PDF document text
    • http://smithmurdock.com/wp-content/plugins/formcraft/file-upload/server/content/files/161471823beffd---dixuredidedes.pdfIn PDF document text
    • http://flixgolf.com/ckeditor/ckfinder/userfiles/files/nutunuxuzebebez.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_off0000e04c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE04C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f863.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF863 10824 bytes
SHA-256: 88ad215210977cdb4b01943feb3ce5caa46bd3eec36f9d26309c340d08a52e14
font_02_sfnt_off0001113a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1113A 19056 bytes
SHA-256: 1e2c16291ce05a2ec6b54e0816469ad5e432a3aae8b476ab15bbb7f527d83c74

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