Malicious PDF — malware analysis report

Static analysis result for SHA-256 16c11cdd33e44673…

MALICIOUS

PDF

82.1 KB Created: 2021-09-06 16:03:16 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 45ced8ce8f63c3f9da34ed62293e9fdb SHA-1: 5a2ab6a4c2539311497b0622c866941b7570625a SHA-256: 16c11cdd33e44673c56c3af95dbc1a52649d316bdca6b805ebebe4d9b1ea5327
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains a large number of embedded URLs, many pointing to compromised WordPress sites and disposable hosting, suggesting a link farm designed to redirect users to malicious content. The presence of a 'download button' heuristic further supports a lure-based attack pattern. No scripts were extracted, but the overall structure and URL distribution indicate a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9955

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://krisoc.ru/uplcv?utm_term=yasin+pdf+file PDF link annotation
    • https://www.unicodesystems.com/wp-content/plugins/super-forms/uploads/php/files/ahrs41b3be692nkaddf802cm50/1793818079.pdfIn PDF document text
    • https://agilitynd.com/wp-content/plugins/super-forms/uploads/php/files/b0b70dcdf5074045e15d69b336882968/xobutizarijowisonemilidul.pdfIn PDF document text
    • http://mouaumfb.com/wp-content/plugins/formcraft/file-upload/server/content/files/160778355ae8a1---94657161486.pdfIn PDF document text
    • http://www.vitrierbxl.be/wp-content/plugins/formcraft/file-upload/server/content/files/160acc16c09475---gokanodosuwalebafuvujit.pdfIn PDF document text
    • http://stalmost.pl/userfiles/file/maxofimegib.pdfIn PDF document text
    • http://langeline.com/ckeditor/upload/files/77842479560.pdfIn PDF document text
    • https://ksmt.edu.np/assets/ckfinder/userfiles/files/nebif.pdfIn PDF document text
    • https://almuhja.net/ckfinder/userfiles/files/tikegapufusujuna.pdfIn PDF document text
    • http://gymostrov.org/gymostrov/userfiles/file/wofajirijusavasom.pdfIn PDF document text
    • https://12shio2.com/contents//files/48815855213.pdfIn PDF document text
    • http://gocreate.termall.pl/upload/fck/file/41645246102.pdfIn PDF document text
    • http://www.investinwielkopolska.pl/application/lib/ckfinder/userfiles/files/wugupolibafute.pdfIn PDF document text
    • http://sgpeo.pl/users//file/kuzezotufego.pdfIn PDF document text
    • https://intervalhousehamilton.org/ckfinder/userfiles/files/pakaresivadakunasovixu.pdfIn PDF document text
    • https://nailseasupportgroup.com/wp-content/plugins/super-forms/uploads/php/files/15cdaa31797e04a36b74b7bd93ab3421/ruwenexevatam.pdfIn PDF document text
    • http://directartdeal.com/uploaded_files/userfiles/files/39927609095.pdfIn PDF document text
    • http://arc-en-cielproduce.com/ckfinder/userfiles/files/41066504281.pdfIn PDF document text
    • http://mclarenquartz.in/ci/userfiles/files/kipupaxize.pdfIn PDF document text
    • http://www.ibadirect.com/wp-content/plugins/formcraft/file-upload/server/content/files/16087a0cae4669---21834596400.pdfIn PDF document text
    • http://mai-colle.jp/userfiles/file/20999775261.pdfIn PDF document text
    • http://sts-logistika.ru/wp-content/plugins/super-forms/uploads/php/files/433850ee97c4a2ad31cc741311ac2f6c/45362556584.pdfIn PDF document text
    • http://plncse.hu/php_data/file/16699754932.pdfIn PDF document text
    • http://montpellier-business-plan.eu/mbp/upload/images/images/upload/ckfinder/kozerodamug.pdfIn PDF document text
    • https://lasvegasrebath.com/wp-content/plugins/super-forms/uploads/php/files/37ecbddffb19193cf6c9fe892c084707/31371439507.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_off0000df36.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDF36 17796 bytes
SHA-256: faf4e40ea77c39bbc698813887726f81e989a0e7c7d3e455bf5c921c17230b1b
font_01_sfnt_off00010cba.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10CBA 10156 bytes
SHA-256: 735547221a2f93b490730458f0845f6a6c75f2741a1668a5c5188371b388d068
font_02_sfnt_off00012380.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12380 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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