Malicious PDF — malware analysis report

Static analysis result for SHA-256 81d55c17e5f69a58…

MALICIOUS

PDF

80.6 KB Created: 2021-09-20 15:08:12 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 446d972909f56621045bfb79229a21b2 SHA-1: 8f752f26b45dc7809b83f3a4e762a4c42eecc7fc SHA-256: 81d55c17e5f69a58367fc7150ebf0cbdcb7f701390a3df517f9e3cdf5679233e
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file contains numerous embedded URLs that form a link farm, directing users to various external sites. Several heuristics indicate that these links are intended to deceive users, with some pointing to compromised CMS uploads and others using disposable hosting. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

Heuristics 7

  • 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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://smidgel.ru/uplcv?utm_term=zombie+simulator+mod+apk
    • https://chandrakantmusicacademy.org/ckfinder/userfiles/files/xuduwituparixuvoxad.pdf
    • https://eastoncn.housemember.com/uploads/files/zopufukuveve.pdf
    • http://alpes-maritimes.proximeo.com/ckfinder/userfiles/files/44257816006.pdf
    • http://fantasypartyentertainment.com/wp-content/plugins/formcraft/file-upload/server/content/files/16141d23b8ade5---5306050403.pdf
    • http://wintec-samu.hu/uploads/files/deraw.pdf
    • https://aimhc.com/userfiles/file/55630454709.pdf
    • http://librojuridico.com/aym_images/files/59570717160.pdf
    • https://mkting.com.co/wp-content/plugins/super-forms/uploads/php/files/c74e31e57c1d36a5077ca06b16f45728/45532044237.pdf
    • http://asia-test.informacittadino.net/media/files/68016544275.pdf
    • http://gayaarchi.com/userfiles/file/20210902190518.pdf
    • http://clinivetmadonnadirosa.eu/userfiles/files/98810902517.pdf
    • https://bahceneryaman.net/public/content-images/files/gipuve.pdf
    • http://langfordfinancialservices.com/userfiles/files/71856049824.pdf
    • http://staractivecollection.com/resimler/site/files/86261204143.pdf
    • http://files.ibiza-ferien.de/file/54302840452.pdf
    • https://parisautotravel.com/wp-content/plugins/super-forms/uploads/php/files/sqgevi96uihl7rn7h1sa2ou8n2/litarikopapasevuzakedot.pdf
    • http://anael.fr/fckeditor/userfiles/file/646747590.pdf
    • https://trade.inter-ural.ru/ckfinder/userfiles/files/12922714093.pdf
    • http://cheliabinsk.realxenon.ru/uploads/files/zanosami.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_off0000d415.bin
4b326b6f671cf1bb809797c2cab1373abd153c9350ed81523235b81f94fb8992
pdf-font-stream PDF embedded font (sfnt) at offset 0xD415 18808 bytes
font_01_sfnt_off0001049b.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x1049B 16792 bytes
font_02_sfnt_off00011cb2.bin
0c6a8cd08c67be86a3a96f8f2ad948b7d8245e434b401e743eb7d3231c9492b5
pdf-font-stream PDF embedded font (sfnt) at offset 0x11CB2 10744 bytes