Malicious PDF — malware analysis report

Static analysis result for SHA-256 81f1615792559e98…

MALICIOUS

PDF

82.2 KB Created: 2021-09-01 08:23:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: b062a2126fb94eb2f7d9e1279dedc6cb SHA-1: 9195187f043e6bdab963cbdceb985c96b49dd7f8 SHA-256: 81f1615792559e980fa84740c6e3283e10dbbbe03ad710cd57d404af81df279b
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous external links, many pointing to compromised CMS upload storage or disposable hosting, suggesting a link farm designed to redirect users. The presence of PDF_URI and PDF_SEO_DISPOSABLE_LINK_FARM heuristics further supports this. While no scripts were explicitly extracted, the PDF format itself can embed JavaScript, which could be used to facilitate the redirection or exploit vulnerabilities.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9990

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
  • 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://smidgel.ru/uplcv?utm_term=feast+of+st+christopher PDF link annotation
    • http://fructusartis.com/i/File/82258945493.pdfIn PDF document text
    • http://educasters.co/ckfinder/userfiles/files/fosogogufefikevebugizuve.pdfIn PDF document text
    • https://elicopter-de-inchiriat.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160b4359523bba---tagaxabe.pdfIn PDF document text
    • http://urbanconstructions.org/images/uploadedimages/file/88348339076.pdfIn PDF document text
    • https://bayihoki99.com/contents//files/furujofini.pdfIn PDF document text
    • http://budka39.ru/files/gelirisawoluka.pdfIn PDF document text
    • https://hcs1000.org/wp-content/plugins/super-forms/uploads/php/files/01cdffc0e3d0c4f3898d280599f189ef/xubazetidimid.pdfIn PDF document text
    • http://medica-brno.com/files/84481441184.pdfIn PDF document text
    • https://www.alongsideasia.com/wp-content/plugins/super-forms/uploads/php/files/6c328d53f3a1b9bec47a1852903fa379/13546431761.pdfIn PDF document text
    • https://horacebatten.com/ckfinder/userfiles/files/3495239507.pdfIn PDF document text
    • https://protradingindia.net/userfiles/file/mifatopoxegikatipetu.pdfIn PDF document text
    • http://zaun-produzent.de/userfiles/file/sufopaxesofexonozozow.pdfIn PDF document text
    • http://msinziniering.com/userfiles/file/surapusamoxekujikigetutuk.pdfIn PDF document text
    • http://ggbris.com/slbdavbatala/userfiles/file/lefafifipenitigubekosirud.pdfIn PDF document text
    • http://www.kidnuri.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bccb3869e17---makemiwopulaz.pdfIn PDF document text
    • https://playgametoday.ru/wp-content/plugins/super-forms/uploads/php/files/c6566cc4ae73a398162fee5279e58b63/32094914781.pdfIn PDF document text
    • http://lawcab.ru/wp-content/plugins/formcraft/file-upload/server/content/files/160886c01467d8---97697712010.pdfIn PDF document text
    • https://www.esicm-old.org/admin/lib/ckfinder/userfiles/files/59414552121.pdfIn PDF document text
    • http://vswet.ru/f/81468606458.pdfIn PDF document text
    • http://hrzservices.com/uploadfiles/file/20236435768.pdfIn PDF document text
    • https://mebelpozakazu.ru/wp-content/plugins/super-forms/uploads/php/files/ba06590df9110b5457d3cfc2a80a7334/28112435679.pdfIn PDF document text
    • http://bright-mineral.com/uploadfile/file/2021072318171167.pdfIn PDF document text
    • http://puntolinea.org/userfiles/files/34715291676.pdfIn PDF document text
    • https://wlao.on.ca/wp-content/plugins/super-forms/uploads/php/files/7c92e77ef68ef2ca585e5e6b3a9b8727/94614559460.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_off0000ddbc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDDBC 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f5d3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF5D3 10404 bytes
SHA-256: 1adb258453cdb5f8e8e062213a8fcbc8818211fd8685e24d062ba21a9d5ef695
font_02_sfnt_off00010d83.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10D83 17504 bytes
SHA-256: e25f847e3e1ac214180b5bd70a75d1293350ede73e4fd0881e47003434cf43cd

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