Malicious PDF — malware analysis report

Static analysis result for SHA-256 91b4129de94d29fb…

MALICIOUS

PDF

90.1 KB Created: 2021-09-05 23:45:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 6c5879cc458fe6328e8c1836c742d288 SHA-1: 2f924cf08bd91fc65ab3f4532f4b9c54567dcb45 SHA-256: 91b4129de94d29fb0ce0d0b0c9f2509f0e0cbdc061ad8aa1a90d8a525c2c414b
156 Risk Score

Malware Insights

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

This PDF file was flagged by multiple heuristics as malicious, including a critical ClamAV detection and an ML classifier indicating a high probability of maliciousness. The document functions as a link farm, containing numerous URLs pointing to various websites, some of which are hosted on compromised CMS uploads. This suggests an attempt to manipulate search engine rankings or redirect users to potentially malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9949

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 https://ikincielinmak.com/upload/ckfinder/files/4887340938.pdf In PDF document text
    • http://taociren.com/upload/file/21072120425832875251hjmvczbul1.pdfIn PDF document text
    • http://lilit-realty.com/wp-content/plugins/super-forms/uploads/php/files/5hltefcbfj91qfgcb5272ml4r7/3735197320.pdfIn PDF document text
    • https://olivierdaulte.com/ckfinder/userfiles/files/jekux.pdfIn PDF document text
    • https://expresstestingatl.com/wp-content/plugins/super-forms/uploads/php/files/1bd33b5833a454df8ba843824e5caef3/77537033620.pdfIn PDF document text
    • http://psycare-spb.com/userfiles/file/xamarisale.pdfIn PDF document text
    • https://www.tessilgiada.it/wp-content/plugins/formcraft/file-upload/server/content/files/16099e6c1ab9e2---nozuxutijasogelixafu.pdfIn PDF document text
    • https://parisautotravel.com/wp-content/plugins/super-forms/uploads/php/files/7rh9a44jnkf38raj338rlg1bi4/4786029144.pdfIn PDF document text
    • https://izharfoster.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612c738d39c76---71161190134.pdfIn PDF document text
    • http://uchid.com/uploads/file/20792498565.pdfIn PDF document text
    • http://discoveryenglish.org/wp-content/plugins/formcraft/file-upload/server/content/files/160773fea534fe---zagegevobajogive.pdfIn PDF document text
    • http://www.holderit.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a7e3b124e5e---54163739223.pdfIn PDF document text
    • https://evocative.ru/wp-content/plugins/formcraft/file-upload/server/content/files/16120905dcf1dd---zofaxuxaroberazagulis.pdfIn PDF document text
    • http://niszczeniewaw.pl/userfiles/file/72707456881.pdfIn PDF document text
    • http://archpiudue.com/userfiles/files/dopomiri.pdfIn PDF document text
    • http://indyskischool.com/ckfinder/userfiles/files/47493598580.pdfIn PDF document text
    • http://crm333.com/documentos/file/mizexidotamadide.pdfIn PDF document text
    • http://russkiivopros.com/images/FCKeditor/file/87579808608.pdfIn PDF document text
    • https://www.edutechusa.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608f241b87bcb---wilojufet.pdfIn PDF document text
    • http://thekitchendesignstudio.org/uploads/files/zetizazefopinofeki.pdfIn PDF document text
    • http://irinaburmistrova.ru/files/5652199830.pdfIn PDF document text
    • http://denki-shonan.com/uploadsfile/tilunad.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/DOqCt-cVA4I/uplcv?utm_term=core+java+volume+ii+advanced+features+8th+edition+pdfPDF 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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d96e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD96E 11420 bytes
SHA-256: 1695d45002bbb3d6b087cfc2a86b27685a1513a115717ae6219b9879349b4b0d
font_01_sfnt_off0000f435.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF435 21720 bytes
SHA-256: 2323fd2d9c5059cceda5c60de27dab9d45a44cc2b43279327dc7331639bb5fda
font_02_sfnt_off00012bb3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12BB3 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_03_sfnt_off000143c4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x143C4 16232 bytes
SHA-256: 01cd0e4798e93fb086042d610f43ddeed7bf091af48aa863f5c4a4f61b651684

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