Malicious PDF — malware analysis report

Static analysis result for SHA-256 16cd8686a074da95…

MALICIOUS

PDF

73.2 KB Created: 2021-10-03 15:56:16 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-02
MD5: 6312f0477505f1fc38f1f9fd14ae77fd SHA-1: 692ddb587cc22b2de87feeac18192221d1e7fdad SHA-256: 16cd8686a074da95f3091ea7707c39ec013581051cf613cf25314e3b7d355c0a
176 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF document was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with many URLs pointing to potentially compromised WordPress sites or disposable hosting. The document body, though heavily obfuscated, suggests a callback phishing lure, prompting users to contact a number for issues like billing or fraud.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9963

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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.
  • Callback phishing phone lure medium SE_CALLBACK_LURE
    Document asks the user to call a phone number in billing, refund, subscription, fraud, or security context — consistent with callback phishing or tech-support scam patterns. Suppressed for legitimate-issuer (IRS/gov/official-form) documents that carry no urgency or charge/dispute escalation.
  • 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 http://faurau.com/luodan/images/userfiles/file/23947003373.pdf In PDF document text
    • http://gewidor-gmbh.de/uploads/files/91579108984.pdfIn PDF document text
    • http://zamgph.com/uploads/file/291312032913.pdfIn PDF document text
    • https://www.isnb.co.uk/wp-content/plugins/super-forms/uploads/php/files/096643d5f049f365cef5691277d03330/movilijupirebofo.pdfIn PDF document text
    • http://www.fan-consultants.com.tw/ezadmin/ckfinder/userfiles/files/56112997517.pdfIn PDF document text
    • http://gesundheit-im-blog.de/userfiles/file/38082307914.pdfIn PDF document text
    • https://harmony.im/userfiles/file/46486283359.pdfIn PDF document text
    • https://mavismanagement.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614d5f78cd9c9---gobopax.pdfIn PDF document text
    • https://optimumquestsolutions.com/ckfinder/userfiles/files/27591537876.pdfIn PDF document text
    • https://leosservices.com/userfiles/file/tezaluzudabibiba.pdfIn PDF document text
    • https://bevillelecomte.ovh/ckfinder/userfiles/files/56506774761.pdfIn PDF document text
    • http://ozdermusavirlik.net/userfiles/file/13852463506.pdfIn PDF document text
    • http://healingtown.org/userData/board/file/doxozotumogikiw.pdfIn PDF document text
    • https://amigo-shop.105h.net/upload/files/83378487752.pdfIn PDF document text
    • https://suksesunited.com/contents/files/mebalore.pdfIn PDF document text
    • http://electric-kernbichler.at/51276696453.pdfIn PDF document text
    • http://peterpan1996.it/userfiles/files/katajapubedolunozazok.pdfIn PDF document text
    • https://www.rockandroll.blog.br/wp-content/plugins/super-forms/uploads/php/files/kld5hvl744rpao6nr9knjt1gcv/pinirasafafonidilubuv.pdfIn PDF document text
    • http://bigbazar.cz/is/images/FCKeditor/File/1451152554.pdfIn PDF document text
    • https://bentzendesign.se/wp-content/plugins/formcraft/file-upload/server/content/files/161596795960fc---sumovegarubazokizirep.pdfIn PDF document text
    • http://gd-weimi.com/upfolder/e/files/20210921002527.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/ngfLrbzwjls/uplcv?utm_term=merits+and+demerits+of+monarchyPDF link annotation
    • https://cakamuzejs.riga.lv/ckfinder/userfiles/files/tonimurozojuvezewamuge.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_off0000bac5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBAC5 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000d2d7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD2D7 17248 bytes
SHA-256: 9c71051028106b11a4c32d77ba4c28bff6e71ee17c397b18314862fe4db93ab6
font_02_sfnt_off0000fef0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFEF0 10800 bytes
SHA-256: 1bf42232593a0ebdfc09067a05caaa8d32217882d81bef192d397d92345d5c82

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