Malicious PDF — malware analysis report

Static analysis result for SHA-256 c4b285d9f3ffcae2…

MALICIOUS

PDF

135.4 KB Created: 2021-09-16 18:00:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 822948d83ed2338034e459b2d355e924 SHA-1: 56c4db8a5a9f1a876e16a364c66b8f9c416a2f16 SHA-256: c4b285d9f3ffcae26d7cbfdd1748b5e5279fc33b652d0776062cc3d3bf1eb566
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF file was flagged by multiple heuristics, including a machine learning classifier and ClamAV, indicating malicious intent. The presence of numerous external URIs, many of which are part of a link farm on disposable hosting, suggests a phishing or malware distribution campaign. The document body, though heavily obfuscated, contains metadata indicating it was generated by wkhtmltopdf, a tool often used to create malicious PDFs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9855

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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.
  • 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://ketchas.ru/uplcv?utm_term=android+11+redmi+4x PDF link annotation
    • http://toroisg.com/public/images/files/90587319639.pdfIn PDF document text
    • https://oreopay57.com/ckfinder/userfiles/files/liboj.pdfIn PDF document text
    • http://oticonshop.com/ckfinder/userfiles/files/10527436291.pdfIn PDF document text
    • https://meritumptt.pl/dokumenty/file/benifikukipego.pdfIn PDF document text
    • http://opuspointpartner.com/ckfinder/userfiles/files/jizumapawinopoteradurig.pdfIn PDF document text
    • http://24cvety.ru/upload/files/firatidilulemoxoz.pdfIn PDF document text
    • http://stlnsk.ru/uploads/file/tusaxumafesebifaxuz.pdfIn PDF document text
    • http://qdjshg.com/files/file/xaribojijowofeb.pdfIn PDF document text
    • http://leeandrewdavison.com/download/69226331201.pdfIn PDF document text
    • https://philly.drinkpoint.com/uploads/files/vilupur.pdfIn PDF document text
    • https://duhocblueocean.vn/ckfinder/userfiles/files/95745600161.pdfIn PDF document text
    • http://puntolinea.org/userfiles/files/folavo.pdfIn PDF document text
    • https://www.kiemtoandongnghi.com/public/plugins/ckfinder/userfiles/files/nenugamojikefewagutokiwu.pdfIn PDF document text
    • https://kermiradiatoriai.lt/images/files/majemixibawipele.pdfIn PDF document text
    • http://www.globalnautique.nl/upload/files/vaburakuba.pdfIn PDF document text
    • http://www.yemany.com/yemfiles/files/turutukisinusebuwemomagi.pdfIn PDF document text
    • https://kamber.dk/wp-content/plugins/super-forms/uploads/php/files/33bf33e80012881944ffc38e3f49dabf/81754175823.pdfIn PDF document text
    • https://www.spitalmoldovanoua.ro/ckfinder/userfiles/files/xufijanizugutavisujafan.pdfIn PDF document text
    • http://hzdsbg.cn/uploadfile/1630792488.pdfIn PDF document text
    • http://palenice.net/obrazky_clanky/file/xerekobafadifawivi.pdfIn PDF document text
    • https://saftanton.dk/wp-content/plugins/formcraft/file-upload/server/content/files/16137d3869c962---zagojepabegiso.pdfIn PDF document text
    • https://moyaexpresss.com/ckfinder/userfiles/files/binamoralox.pdfIn PDF document text
    • http://giustizianuova.it/userfiles/file/76522631365.pdfIn PDF document text
    • https://funbugs.ie/files/file/84834865385.pdfIn PDF document text
    • http://ssteelelaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/68697101699.pdfIn PDF document text
    • http://www.siposferenc.hu/html/37625345188.pdfIn PDF document text
    • http://erodiertechnik-wenzel.de/userfiles/file/3687489984.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_off0001aeae.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1AEAE 10148 bytes
SHA-256: bb985ddeccf52ab80628e7f8f9d0bae1df68f7db657c829fb7875d43711bd397
font_01_sfnt_off0001c55d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1C55D 19116 bytes
SHA-256: 11e9387b9aac6af63990ece851c396f2b502a8ee412eddff7cbb0280d624ccb5
font_02_sfnt_off0001f72a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1F72A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1