Malicious PDF — malware analysis report

Static analysis result for SHA-256 4394329c2137beb6…

MALICIOUS

PDF

82.4 KB Created: 2021-09-09 07:03:00 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 9a23e36fe8a9574894cef10dcb25a4b7 SHA-1: 274a8cf4c609f9c7ea7e9ec6c8076fd0eff2985f SHA-256: 4394329c2137beb61458563ec429b0e84b29919f4caab1d9c2d6a8c8bf29cd28
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file is identified as malicious by ClamAV and an ML classifier, and exhibits characteristics of a link farm designed to host and distribute other malicious PDFs. Several heuristics indicate the PDF is part of a link farm, with many URLs pointing to compromised WordPress sites or disposable hosting, suggesting an attempt to obscure the true origin of malicious content. The presence of embedded URLs, even if some are marked benign, and the overall structure point towards a phishing or malware distribution scheme.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

Heuristics 6

  • 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.
  • 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://kungfuclasshongkong.com/louis/taichi/ckfinder/userfiles/files/xujeseretut.pdf In PDF document text
    • https://alsultantrading.ae/userfiles/files/pefetilutupigafisisime.pdfIn PDF document text
    • http://mirembeestate.co.ug/wp-content/plugins/formcraft/file-upload/server/content/files/16133d59f09c53---nuroxediv.pdfIn PDF document text
    • http://dj-venci.com/uploads/pages/files/29948540209.pdfIn PDF document text
    • http://mnogonomerov.ru/uploads/file/9851160352.pdfIn PDF document text
    • http://www.ponderosafestival.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612f806fa768b---84970324129.pdfIn PDF document text
    • https://qualitycountscleaning.com/wp-content/plugins/super-forms/uploads/php/files/a334907030ba25d63ddb7441a6edf19e/zarepujugosi.pdfIn PDF document text
    • http://shlawllc.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/36356351979.pdfIn PDF document text
    • https://bishopsalamatkhokhar.org/userfiles/file/24694604807.pdfIn PDF document text
    • https://www.costaverde.it/wp-content/plugins/formcraft/file-upload/server/content/files/16138080d25a67---54367128118.pdfIn PDF document text
    • https://dmitrovka-zn.ru/admin/ckfinder/userfiles/files/nitawelewe.pdfIn PDF document text
    • https://www.tonygssoulfood.com/wp-content/plugins/super-forms/uploads/php/files/2160ca7d0220e0daa7483a16e073a7aa/vuvuzakikiwifosoko.pdfIn PDF document text
    • http://louisefarmersmith.com/admin/ckeditor/ckfinder/userfiles/files/geloradevov.pdfIn PDF document text
    • https://carthink.org/wp-content/plugins/formcraft/file-upload/server/content/files/161344f9658592---nevavarogawavukivotu.pdfIn PDF document text
    • https://tarzminder.com/resimler/files/76055113758.pdfIn PDF document text
    • https://uleiuri.ro/userfiles/file/65726359002.pdfIn PDF document text
    • https://honghow.com/ckfinder/userfiles/files/televogetigalatipapamipuw.pdfIn PDF document text
    • https://picinterior.com/ckfinder/userfiles/files/jowilawovodol.pdfIn PDF document text
    • http://kovofilm.cz/userfiles/file/tozokajesevuret.pdfIn PDF document text
    • https://www.tonygssoulfood.com/wp-content/plugins/super-forms/uploads/php/files/1fe77c2709e4ab6deeebdbbaec4726b7/46834020440.pdfIn PDF document text
    • https://superchills.com/userfiles/file/45336369706.pdfIn PDF document text
    • http://ap116.ru/userfiles/file/bunafevekufiwufi.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/DOqCt-cVA4I/uplcv?utm_term=download+office+apk+for+androidPDF link annotation
    • 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_off0000db52.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDB52 10528 bytes
SHA-256: a0edcba62b77befd87567c0f8b4c4cf8f43f7b5961b24d1097bf2a6d14ae01a5
font_01_sfnt_off0000f35c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF35C 18928 bytes
SHA-256: cb3303d4f670c5f49b588c65b582f0d74d1bc8de0b012e80987716471b78bf84
font_02_sfnt_off000123d3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x123D3 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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