Malicious PDF — malware analysis report

Static analysis result for SHA-256 a4238f6c7c6233c8…

MALICIOUS

PDF

76.4 KB Created: 2021-09-14 18:18:17 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: d1fbbcc1ed82f57edb00be2d9874d36d SHA-1: f8a91735e40418caa16592b17a6096a1b2a3c781 SHA-256: a4238f6c7c6233c83cbe6b276f7350db79df3c0bb575375f75e20e9925bc8cda
146 Risk Score

Malware Insights

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

The PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics identified it as a link farm with numerous disposable URLs, suggesting a phishing or malware distribution scheme. The document body, though heavily obfuscated, contains metadata from wkhtmltopdf, indicating it was likely generated programmatically to host these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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
  • 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://toshiteriyakiburien.com/uploads/files/10271660723.pdf In PDF document text
    • http://lapmaymn.samdigroup.vn/app/webroot/upload/files/6356765405.pdfIn PDF document text
    • http://www.ctmmaximoravenna.com/ckfinder/userfiles/files/77679044498.pdfIn PDF document text
    • https://accuratesearch.com/userfiles/file/2125774107.pdfIn PDF document text
    • http://matrixuniverzum.eu/wp-content/plugins/formcraft/file-upload/server/content/files/161386a51e6950---51977173589.pdfIn PDF document text
    • https://gulfsupremesa.com/ckfinder/userfiles/files/gikomol.pdfIn PDF document text
    • https://medsplus.us/admin/images/file/18171458211.pdfIn PDF document text
    • https://talaa-obour.com/webmisr/uploadwebmisr/file/rilazuvox.pdfIn PDF document text
    • http://519pf.com/userfiles/files/vusosatofefepekebodolef.pdfIn PDF document text
    • https://parkettworld.com/upload/files/33945485189.pdfIn PDF document text
    • https://cjsc.se/ckfinder/userfiles/files/dolug.pdfIn PDF document text
    • https://meesens.be/KrMee/Tekstverwerker/xizedapebenewi.pdfIn PDF document text
    • http://moskvaznaet.ru/upload/files/57743075481.pdfIn PDF document text
    • http://usmleworkout.com/files/file/xubagexitule.pdfIn PDF document text
    • https://lorus.rs/files/83491259190.pdfIn PDF document text
    • http://archissimo.eu/userfiles/files/97355735865.pdfIn PDF document text
    • http://architettoangeli.it/userfiles/files/22569957554.pdfIn PDF document text
    • https://danielstrehlau.com/userfiles/file/bozaga.pdfIn PDF document text
    • http://daithanhnam.com/upload/files/82510851863.pdfIn PDF document text
    • http://dietetyka-24.pl/images/files/43307344699.pdfIn PDF document text
    • http://boonfagrandhome.com/user_img/files/soxazegaratebiliviwuju.pdfIn PDF document text
    • http://diamantina-joaillerie.com/ckfinder/userfiles/files/78621068067.pdfIn PDF document text
    • https://carmelocuritiba.com.br/ckfinder/userfiles/files/kepevinajafom.pdfIn PDF document text
    • http://adwokaci-pila.pl/userfiles/file/lojaduwepuseniwapolalag.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/FevRqgeaUVY/uplcv?utm_term=download+gta+san+andreas+apk+and+obbPDF 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_off0000c4aa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC4AA 17732 bytes
SHA-256: 59791c060afdd03d15637ebda66a3425ad57cb0fe7ec20e06d0d05249cf9d708
font_01_sfnt_off0000f2f0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF2F0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010b07.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10B07 10792 bytes
SHA-256: ff213a510b29389db83b85abe7b94fba707852de5d2d9d7adf6e0726c7d2060a