Malicious PDF — malware analysis report

Static analysis result for SHA-256 51fba8303a0d7595…

MALICIOUS

PDF

74.4 KB Created: 2021-09-04 21:37:12 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: c555d2b3d336544e6aaab0e1b89f6e29 SHA-1: 9eb364e31e31cce0f081a3538cd5c3797d81986a SHA-256: 51fba8303a0d7595f19c72da61649ee6272c0ccb376ebed109e04e6f52b0be14
164 Risk Score

Malware Insights

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

This PDF contains embedded JavaScript and numerous external links, many pointing to compromised WordPress sites. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' indicates a deliberate attempt to create a link farm, likely to direct users to malicious or phishing websites. The ML classifier and ClamAV detection strongly suggest malicious intent, possibly involving exploitation or redirection to a second-stage payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9953

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.
  • 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.
  • 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://medvor.ru/uplcv?utm_term=sampieri+2019+pdf PDF link annotation
    • https://kermoulin.com/userfiles/file/37618744134.pdfIn PDF document text
    • https://optimustelecoms.com/ckfinder/userfiles/files/95464517429.pdfIn PDF document text
    • https://zzarosiscarampola.it/file/liripinorojiribelopomekix.pdfIn PDF document text
    • https://coastalholidayproperty.com/ckfinder/userfiles/files/25247705103.pdfIn PDF document text
    • http://liccuza.ro/stiri_files/file/23342874902.pdfIn PDF document text
    • https://www.burit.net/wp-content/plugins/formcraft/file-upload/server/content/files/1609418fee5b31---36454160965.pdfIn PDF document text
    • https://pankalconstructora.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c104cc96b07---61485528421.pdfIn PDF document text
    • https://noble-worldwide.com/wp-content/plugins/super-forms/uploads/php/files/078b2b695f720fef7c89b72f4914676a/mumipuvigovofezom.pdfIn PDF document text
    • https://www.mii.net/wp-content/plugins/super-forms/uploads/php/files/bf20951ff7e5718cfd5581910b787e23/sedilasutorir.pdfIn PDF document text
    • http://woods-china.cn/ci2/userfiles/files/20210809034827.pdfIn PDF document text
    • http://northmarking.com/userfiles/files/58299810418.pdfIn PDF document text
    • http://cloverdiamond.com/file/78468733666.pdfIn PDF document text
    • https://veglifekc.org/wp-content/plugins/super-forms/uploads/php/files//misimuxuxowad.pdfIn PDF document text
    • http://autosoftware.company/autoresponders_images/files/laxizupezoguf.pdfIn PDF document text
    • http://thegrcinstitute.org/app/webroot/js/ckfinder/userfiles/files/lifugilo.pdfIn PDF document text
    • http://miroslaws.com/ckfinder/userfiles/files/purubujepeludofunog.pdfIn PDF document text
    • http://www.motionmantra.com/userfiles/files/43202784296.pdfIn PDF document text
    • https://drddvichitra.com/userfiles/file/taratuvas.pdfIn PDF document text
    • https://haps.company/wp-content/plugins/super-forms/uploads/php/files/90jombtu3m32e8su3m2itf4o33/63368004630.pdfIn PDF document text
    • http://greenhousehotel.vn/uploads/image/files/rarepir.pdfIn PDF document text
    • https://kawanmto.org/contents//files/79350696608.pdfIn PDF document text
    • http://greenbrier101.com/userimages/41490941665.pdfIn PDF document text
    • http://www.ncstarim.com.tr/wp-content/plugins/super-forms/uploads/php/files/7vku0uu4h1dhte78pgvp48joc0/zabawuvaw.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_off0000bf3f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBF3F 10660 bytes
SHA-256: 789dadd50b4f1dc2a508d005b30608374cc76a4e94baa879210456fd54a9addf
font_01_sfnt_off0000d7bb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD7BB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000efcd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEFCD 17364 bytes
SHA-256: 9e312ec25324ac83eb2c7db6f4cf7fa9df5fad79b15a98b6a9223e606ea93a77

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