Malicious PDF — malware analysis report

Static analysis result for SHA-256 81a9fccb789f1454…

MALICIOUS

PDF

107.1 KB Created: 2021-08-21 20:55:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-22
MD5: bc4f2bf1fba968331ea530667fb0d2e9 SHA-1: 4b73ca1c7c67c8d7becbc75ae8394476eb295469 SHA-256: 81a9fccb789f14543adc98f7c6183ad45d505426a58f183e3ae063561625aec8
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF file was identified as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. Heuristics reveal it functions as a link farm, with numerous URLs pointing to compromised CMS uploads and disposable hosting, suggesting a phishing or malware distribution scheme. The embedded URLs and the overall structure strongly suggest an attempt to lure users to external malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9985

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 http://sazjah.com/wp-content/plugins/formcraft/file-upload/server/content/files/16086d8c554099---wojuxawuduwobegera.pdf In PDF document text
    • http://nitexprofi.cz/userfiles/file/87654076042.pdfIn PDF document text
    • https://www.novet.de/wp-content/plugins/formcraft/file-upload/server/content/files/160c04392cb91b---83312545746.pdfIn PDF document text
    • http://megat.pl/uploaded/fck_files/file/45845437132.pdfIn PDF document text
    • https://suma.ca/upload/editor/file/76261615401.pdfIn PDF document text
    • http://baikalspring.ru/ckfinder/userfiles/files/gonadazirodotud.pdfIn PDF document text
    • https://www.qlsny.com/wp-content/plugins/super-forms/uploads/php/files/6a8881b9eb251e81938119e14a80060a/53287719944.pdfIn PDF document text
    • http://domeinbeverdonk.be/assets/files/file/24109063057.pdfIn PDF document text
    • http://www.emporiocaritaspisa.it/wordpress/wp-content/plugins/formcraft/file-upload/server/content/files/160853c8cddf2e---mamexonun.pdfIn PDF document text
    • http://ourjamesfamilyhistory.com/clients/1/14/146a9f92d0a296c7c29e793db058bb30/File/15666855134.pdfIn PDF document text
    • https://www.albriug.com/static/editor/ckeditor/ckfinder/upfile/files/92832273036.pdfIn PDF document text
    • http://slowjamsundays.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609b58a1cf7d3---5579224696.pdfIn PDF document text
    • http://eros-arena-reutlingen.de/eros/userfiles/file/dawinikefepufitonijed.pdfIn PDF document text
    • http://dongphuctqueen.com/upload/files/12409151697.pdfIn PDF document text
    • https://greenways.at/userfiles/file/xenuzu.pdfIn PDF document text
    • http://sushikyototogo.com/uploads/files/20682927572.pdfIn PDF document text
    • http://www.elsecretodelolivo.com/wp-content/plugins/formcraft/file-upload/server/content/files/160803d7ddb60d---minezufaxejojugage.pdfIn PDF document text
    • http://z-i-f.ru/userfiles/file/wixijoguxevuvali.pdfIn PDF document text
    • http://kancelaria-perfect.pl/app/webroot/media/files/ninujaloluk.pdfIn PDF document text
    • http://abwnickersonplaza.com/uploads/files/jawilimozunod.pdfIn PDF document text
    • http://sherwoodchambergolf.com/ckfinder/userfiles/files/13377229335.pdfIn PDF document text
    • https://digireg.at/upload/gofaf.pdfIn PDF document text
    • https://ercrs.org/wp-content/plugins/super-forms/uploads/php/files/svsfkh4evi552m0poeb62gn65f/912893513.pdfIn PDF document text
    • http://learnazia.com/fck/imagesfile/87530502896.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/PmAiG5ZyT-k/uplcv?utm_term=diferencias+ventajas+y+desventajas+de+los+inventarios+en+proceso+de+seguridad+y+estacionalPDF 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_off000138eb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x138EB 18376 bytes
SHA-256: ac09150c4cd832f2cb7cbd4e60ec790d509458e474ac591e6b582857da4e9507
font_01_sfnt_off00016869.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x16869 11204 bytes
SHA-256: 055b1424b43d9797bb38bbabb4959554c82babe4362ea650883b865ac3d87a08
font_02_sfnt_off00018297.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x18297 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1