Malicious PDF — malware analysis report

Static analysis result for SHA-256 b91093264085d1b5…

MALICIOUS

PDF

95.4 KB Created: 2021-08-06 15:13:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-22
MD5: 6999e6da04e4b1d59ef43cfb9ea3beea SHA-1: 14701a15e435a908b0458002908f93718b245cd5 SHA-256: b91093264085d1b574139f7bc0f146b3487192c331ee81e0c9ea593bc31591c5
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF document was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains a large number of embedded URLs, many pointing to compromised WordPress sites or disposable hosting, suggesting a link farm designed to redirect users to malicious content. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, indicating it's not intended for human readability but rather as a container for malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9947

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://medvor.ru/uplcv?utm_term=material+didactico+para+primer+grado+de+primaria+para+imprimir+gratis PDF link annotation
    • https://mtmhomeschool.com/mycms/uploadedimages/editorUploadedImages/file/83653611179.pdfIn PDF document text
    • https://www.costaverde.it/wp-content/plugins/formcraft/file-upload/server/content/files/16092e9468a790---1149623592.pdfIn PDF document text
    • http://gojjang.com/uploads/files/65964778793.pdfIn PDF document text
    • https://podiummagazinenews.com/ckfinder/userfiles/files/86872204841.pdfIn PDF document text
    • http://saovietgroup.com/upload/FCK/file/tobodugigafisavakef.pdfIn PDF document text
    • https://callhfelectric.com/wp-content/plugins/formcraft/file-upload/server/content/files/160759ab0853b8---gegatibolufizil.pdfIn PDF document text
    • https://expobar.vn/app/webroot/files/images/pages/files/kumibelorox.pdfIn PDF document text
    • https://verandapattaya.com/userfiles/files/sogawosedevagupevotasupi.pdfIn PDF document text
    • http://inspirationallabels.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16085df3406326---99629696920.pdfIn PDF document text
    • http://accountingworld.in/singhania/downloads/file/70577034479.pdfIn PDF document text
    • http://spoanalyze.com/wp-content/plugins/super-forms/uploads/php/files/bed6f32dcc0a674431df02747e566803/39162168990.pdfIn PDF document text
    • http://ednak.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c34fc01a152---49447024010.pdfIn PDF document text
    • http://hoaiduc.edu.vn/ckfinder/userfiles/files/dajebumudujotezowefug.pdfIn PDF document text
    • http://waukeganeast1980.com/clients/877304/File/27593374837.pdfIn PDF document text
    • https://bringem.de/wp-content/plugins/super-forms/uploads/php/files/dde0cb7549f10964e4baf3336ef495ff/nopidusabetiruse.pdfIn PDF document text
    • https://goactive.hu/wp-content/plugins/super-forms/uploads/php/files/52adf0c7136e5b63d183e9f7e42c6629/gajawavaxurefije.pdfIn PDF document text
    • https://colegiumaniucarei.ro/ckfinder/userfiles/files/wuxazefafifuniwasomuto.pdfIn PDF document text
    • http://3wsystems.com/shipinc/userfiles/files/18689420505.pdfIn PDF document text
    • http://xn--knstlerische-biografie-arbeit-lbd.ch/userfiles/files/nemufoparuriludukekezile.pdfIn PDF document text
    • http://anma.pl/anma_edytor/file/pakuzukuvitipope.pdfIn PDF document text
    • https://hightechrustremovers.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160b8263d0f5e8---43212153045.pdfIn PDF document text
    • https://www.saammohaseb.ir/wp-content/plugins/super-forms/uploads/php/files/aa427955304c7ccd76fa988e6f3847e7/80281022891.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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f9e7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF9E7 10748 bytes
SHA-256: 9d5b819e7c87aa2a309615361d927e9ef8737a39a9bd6a5e8e2e0c98c33226b4
font_01_sfnt_off0001126c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1126C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012a7e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12A7E 17808 bytes
SHA-256: 4ad4a06fc5f64aa9419496dfd86a87e3dac30a94eae54656e46884c36b40d068
font_03_sfnt_off00015768.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15768 16100 bytes
SHA-256: 505f1f16fb057e2a34e7666bb0a43a50f2e0b7bc0033e59b70183295ac12d2e9

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