Malicious PDF — malware analysis report

Static analysis result for SHA-256 7fd836aabbee87f1…

MALICIOUS

PDF

81.4 KB Created: 2021-10-05 23:24:18 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: 622a58dbb7176446a234154d021c0fb2 SHA-1: 92e7a4b556d507f2966e15da3df27c75a4b0e5bc SHA-256: 7fd836aabbee87f1641cf0bee262c32a2024d37cbad8275a61819f6a3a28dd4f
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It contains numerous links to external websites, many hosted on compromised WordPress installations, suggesting a link farm or phishing lure. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, which is often used to create malicious PDFs that mimic legitimate documents.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9955

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 https://laborke.ru/uplcv?utm_term=research+papers+qualities+of+a+good+teacher PDF link annotation
    • http://www.mkkdigital.pt/wp-content/plugins/formcraft/file-upload/server/content/files/16136e726d71e0---wudam.pdfIn PDF document text
    • https://provisionsinternational.com/wp-content/plugins/formcraft/file-upload/server/content/files/16156a687944f1---goxebevalosubekibaniwu.pdfIn PDF document text
    • http://allprintusa.com/admin/images/file/kewitagowozalivawulinax.pdfIn PDF document text
    • https://tranhtreo.com/images/ckeditor/files/pefemetan.pdfIn PDF document text
    • https://greenways.at/userfiles/file/35168355269.pdfIn PDF document text
    • http://sz-frp.com/pic/20210927081924114.pdfIn PDF document text
    • http://termocity.by/pics/files/sajubum.pdfIn PDF document text
    • http://localhomesales.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/16156f9c758851---14713492450.pdfIn PDF document text
    • http://eternalcycle.com/FCKFiles/file/biduxexefufawobisit.pdfIn PDF document text
    • https://coebmsf.com/userfiles/file/sopemi.pdfIn PDF document text
    • https://advicezone.org.uk/wp-content/plugins/super-forms/uploads/php/files/hrga2mcgecgb511olhsnvbu91f/95510985525.pdfIn PDF document text
    • http://softwarefactory.nl/images/file/filiredemovuzavomejataxel.pdfIn PDF document text
    • https://www.andeanskyline.com/wp-content/plugins/formcraft/file-upload/server/content/files/16132ec11cbc73---nodivamexutesisas.pdfIn PDF document text
    • https://namratalakhotia.com/userfiles/files/23793576127.pdfIn PDF document text
    • http://moscowfashion.net/content/xuploadimages/file/70831045302.pdfIn PDF document text
    • https://rockeit.com/userfiles/file/57665388676.pdfIn PDF document text
    • http://dailynewsodia.com/assets/ckfinder/core/connector/php/uploads/files/manevusamanu.pdfIn PDF document text
    • http://bwlpsalisbury.com/uploads/files/27450059405.pdfIn PDF document text
    • https://implant-drill.com/userfiles/file/noxanugelufobuwudolepapik.pdfIn PDF document text
    • http://ekmeta.lt/failai/file/82433070120.pdfIn PDF document text
    • https://nhaban24h.com.vn/wp-content/plugins/super-forms/uploads/php/files/rdltocva14juba2dt1bnu15nrs/jizidujovum.pdfIn PDF document text
    • https://ofertaromania.ro/ckfinder/userfiles/files/24263424896.pdfIn PDF document text
    • https://soswzgierz.pl/web/uploads/files/bulemorufukafurudopu.pdfIn PDF document text
    • http://studiodrago.eu/userfiles/files/nikitabuwuja.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_off0000d9a3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD9A3 11084 bytes
SHA-256: eebe54d0e65023ebaa14623b74f0c29f06e956757698dc0a360311d4f9ed5986
font_01_sfnt_off0000f319.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF319 17412 bytes
SHA-256: 7e8755e9a301024c2d048af53c73c2158a5f6693c540a1dbb691bcb4209c1126
font_02_sfnt_off00011ffb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11FFB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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