Malicious PDF — malware analysis report

Static analysis result for SHA-256 d0f833e3e0547e0d…

MALICIOUS

PDF

78.9 KB Created: 2021-09-16 15:00:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 7b4197478eed7405b8cb8e0351ff16df SHA-1: 08bd7d358f999d8a9ae39145b322f9fc48f97e62 SHA-256: d0f833e3e0547e0df54f8d57571b1f8d4af27905fa2164812a394136dca15be6
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF file was flagged by ClamAV and an ML classifier as malicious, with heuristics indicating it functions as a link farm. Multiple URLs embedded within the document point to compromised CMS uploads and disposable hosting, suggesting an attempt to redirect users to malicious content. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct user-facing lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9958

Heuristics 6

  • 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.
  • 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://jia-longsofa.com/uploadpic/jialong151126/files/202109041951312715.pdf In PDF document text
    • http://studiolegalezullo.eu/userfiles/files/repewekij.pdfIn PDF document text
    • http://www.hotel-margherita.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613db29e5d604---kametejat.pdfIn PDF document text
    • https://edukiya.com/wp-content/plugins/super-forms/uploads/php/files/7125361fea6911132d6d3b6fe76c462c/45790654024.pdfIn PDF document text
    • https://chicagoportablexray.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613567a2a3c16---redov.pdfIn PDF document text
    • http://rund.cz/UserFiles/File/gugubipapewefurebum.pdfIn PDF document text
    • http://evabody.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1613afb62aaf44---25896364269.pdfIn PDF document text
    • https://tese.in/ckfinder/userfiles/files/73743512417.pdfIn PDF document text
    • https://gtijsr.com/userfiles/file/72543375397.pdfIn PDF document text
    • http://skia22.ru/pic/file/domanuzilofuzugav.pdfIn PDF document text
    • https://mirrorlink.com/public/files/files/bavoturil.pdfIn PDF document text
    • http://sayarbobinaj.com/file/bekep.pdfIn PDF document text
    • https://bilegt.mn/userfiles/files/64054358551.pdfIn PDF document text
    • http://vinaktv.com/storage/ckfinder/files/66238749851.pdfIn PDF document text
    • https://rh-h1tapi-turbo.com/contents/files/24264858880.pdfIn PDF document text
    • https://drinkpoint.com/uploads/files/dujumujelekiwekaz.pdfIn PDF document text
    • http://alatasfilms.gr/ILC/img/file/59382537405.pdfIn PDF document text
    • http://cl-pub.com/files/files/91273746551.pdfIn PDF document text
    • https://laneopx.com/wp-content/plugins/formcraft/file-upload/server/content/files/161379e257d0e0---81222693245.pdfIn PDF document text
    • http://omeofest.eu/userfiles/files/zuruvemanidakenet.pdfIn PDF document text
    • http://geologocarmignani.com/userfiles/files/38957144997.pdfIn PDF document text
    • http://icsbc.ru/fuploader/file/55333391584.pdfIn PDF document text
    • http://langeline.com/ckeditor/upload/files/sinupubovitumepe.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/1xuhb7AK25c/uplcv?utm_term=qr+attendance+control+apkPDF 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_off0000cd3b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCD3B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000e54d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE54D 19036 bytes
SHA-256: 062c9ad5a0b5428afa7eca40303177c560323232e9c13c26ddc1f3f46d38ff41
font_02_sfnt_off00011692.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11692 10400 bytes
SHA-256: 03e6f54e8b4d834174a5d48bc41c8c2043613bd5bdc8932a9014c7eef9961092