Malicious PDF — malware analysis report

Static analysis result for SHA-256 3fcbb91fde2aebaa…

MALICIOUS

PDF

83.9 KB Created: 2021-10-04 14:48:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-23
MD5: 0ff9eff5f9db995d776041fd813969e7 SHA-1: 201778eaef2cce5a29e732fd54858209e326c8f6 SHA-256: 3fcbb91fde2aebaa92c95b239fba0d5c1ec06310baddd804b798703981d763c3
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous external URLs, many of which point to disposable hosting and are structured as link farms, a common tactic for phishing or distributing further malware. The presence of PDF_SEO_DISPOSABLE_LINK_FARM heuristic further supports this. No scripts were extracted, but the overall structure suggests it's designed to lure users to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

Heuristics 5

  • 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.
  • 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://philabc.ru/uplcv?utm_term=11+cbse+biology+chapters PDF link annotation
    • http://sinching.com/uploadpic/files/202109190717108139.pdfIn PDF document text
    • http://jtour.vn/userfiles/file/53069917550.pdfIn PDF document text
    • https://sk-elektron.ru/ckfinder/userfiles/files/19669869840.pdfIn PDF document text
    • http://ok-poland.com/userfiles/file/jadugosofitiwen.pdfIn PDF document text
    • http://cmrivestimenti.com/userfiles/files/bibawopulik.pdfIn PDF document text
    • http://worldwidestationeryholdings.com/files/file/55597956626.pdfIn PDF document text
    • http://baharemadinah.com/wp-content/plugins/formcraft/file-upload/server/content/files/16149d7822bf01---82441611663.pdfIn PDF document text
    • http://dream-mebel.com/pic/file/lisido.pdfIn PDF document text
    • http://katachizu.com/img/news/files/50083371248.pdfIn PDF document text
    • https://rugsinc.in/UserFiles/files/bofisotavidukoxuzava.pdfIn PDF document text
    • http://sanarina-coaching.de/ckfinder/userfiles/files/58723426998.pdfIn PDF document text
    • http://thaihotelsale.com/FileData/ckfinder/files/20210910_C3A1CA938B8BF16B.pdfIn PDF document text
    • http://theonejsc.com/userfiles/file/68685800034.pdfIn PDF document text
    • http://obedovice.cz/userfiles/file/94205701469.pdfIn PDF document text
    • https://www.bevillelecomte.com/ckfinder/userfiles/files/xisezonejivajizoz.pdfIn PDF document text
    • https://copperscrap.wasteequipment.net/ckfinder/userfiles/files/19486506454.pdfIn PDF document text
    • https://www.marjojaspers.nl/ckfinder/userfiles/files/257307025.pdfIn PDF document text
    • https://thingstodobahrain.net/ckfinder/userfiles/files/58225163963.pdfIn PDF document text
    • http://www.badischer-kunstverein.de/ckfinder/userfiles/files/52089401840.pdfIn PDF document text
    • http://bangiyaparishadtoronto.ca/bpt/editor/uploadfiles/48608648626.pdfIn PDF document text
    • http://alkanboya.com/files/file///minaluxitemi.pdfIn PDF document text
    • http://lawyermo.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/7048369008.pdfIn PDF document text
    • http://pnmanagementsolutions.in/uploads/27583852779.pdfIn PDF document text
    • http://aygroupmuh.com/image/files/korazizolizapemoriv.pdfIn PDF document text
    • https://yarsan.ru/wp-content/plugins/super-forms/uploads/php/files/94f5de32ae84d2b68f6de0c63095ad96/levupokid.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_off0000e255.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE255 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000fa67.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFA67 18244 bytes
SHA-256: 0877ce45e9688e32379ef4b8c2ae05e67e0ffe77910a574c42215162274cc6df
font_02_sfnt_off00012909.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12909 10756 bytes
SHA-256: 1624a73d72013b4d411e3ce2feac53a02047ce769a9e185f4120ee8c71a3d176