Malicious PDF — malware analysis report

Static analysis result for SHA-256 4a03bff6861b1463…

MALICIOUS

PDF

77.6 KB Created: 2021-09-24 20:44:03 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: a6029ab0ad2818b574e10bbdc5b6329b SHA-1: 1460ea8472db44f51372e9ded8adb58f2f5562fb SHA-256: 4a03bff6861b14638ada04af6ae5545b335974ed97ef7ffaceec00f4b7640b23
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous links to external resources, many of which point to compromised CMS uploads and disposable hosting, indicating a link farm designed to distribute malware. ClamAV detection and ML classification confirm its malicious nature. The presence of embedded URLs and the heuristic firings strongly suggest this PDF is part of a phishing campaign to deliver a secondary payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

Heuristics 7

  • 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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://okcashbagusa.com/uploads/files/fajegonutevuruxuvaf.pdf In PDF document text
    • http://atletika-pardubice.cz/files/file/robisajabenipumov.pdfIn PDF document text
    • https://nhatngudongkinh.com/upload/ckupload/files/86209417685.pdfIn PDF document text
    • https://bilegt.mn/userfiles/files/26805025223.pdfIn PDF document text
    • http://bascobrunswick.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1614014a132a7d---lanofukubu.pdfIn PDF document text
    • https://perfecthospital.org/ckfinder/userfiles/files/nutewijov.pdfIn PDF document text
    • http://ain.proximeo.com/ckfinder/userfiles/files/nutifuxi.pdfIn PDF document text
    • https://facades-et-traditions.com/actualites/file/76740290977.pdfIn PDF document text
    • http://schokozentrale.de/idata/77249221925.pdfIn PDF document text
    • http://uslugi-ogrodnicze.pl/pliki/File/kanutulivolava.pdfIn PDF document text
    • http://czminghe.com/upload/files/surag.pdfIn PDF document text
    • http://girc.ncue.edu.tw/ckfinder/ckfiles/files/78383447999.pdfIn PDF document text
    • https://izyskately.ru/foto/ck/files/54497710973.pdfIn PDF document text
    • http://svazekobciorlice.cz/userfiles/file/rupisobepo.pdfIn PDF document text
    • http://ambulatorioveterinariopisillibertozzi.eu/userfiles/files/8421742417.pdfIn PDF document text
    • https://www.aicsmindia.org/ckfinder/userfiles/files/noxeneliro.pdfIn PDF document text
    • https://xn--bren-mgenwil-gcbf.ch/sites/default/files/fck-uploads/file/16355005811.pdfIn PDF document text
    • https://www.saenger-ohg.de/wp-content/plugins/formcraft/file-upload/server/content/files/161384e5db52e1---torigo.pdfIn PDF document text
    • http://odontoflash.eu/userfiles/files/97603080593.pdfIn PDF document text
    • https://flims.atelierleuthold.ch/userfiles/files/55298793463.pdfIn PDF document text
    • http://www.playerclub.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1614007f93eae4---subevipopofurutufikixapa.pdfIn PDF document text
    • http://irfanmakina.com/depo/sayfaresim/file/6355808043.pdfIn PDF document text
    • http://klusjesindex.nl/images/uploads/37490559815.pdfIn PDF document text
    • http://kovove-ploty-brany-zabradli.cz/UserFiles/File/sozugunikutilirimuxiwor.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/cv9VXjIrmdE/uplcv?utm_term=one+example+of+system+softwarePDF 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_off0000c6f7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC6F7 10752 bytes
SHA-256: 4b44bc5f7a8487ab27bc994395169d4ca5261f0e682c61da58b534d0b4b1a9e6
font_01_sfnt_off0000dfd7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDFD7 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f7e9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF7E9 18792 bytes
SHA-256: dc8bb7769ac2a144a45ffea338f8c2cef37a3562302b763c592786ed53c76ba3

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