Malicious PDF — malware analysis report

Static analysis result for SHA-256 2d8476c6c60e9019…

MALICIOUS

PDF

74.8 KB Created: 2021-09-11 02:20:33 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 6f9116a0fa16286fbf16c18a9a5c8ddf SHA-1: 53a585b5b88ce6de47b988837ba4f7d7955111f9 SHA-256: 2d8476c6c60e9019b069c744963020dbe2ea34b1fe763896f22a221a2ab20ed9
156 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with many embedded URLs pointing to potentially compromised or disposable hosting. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for human readability but rather to host links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9908

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 http://groupkaishan.com/d/files/38270644566.pdf In PDF document text
    • http://rustproofingottawa.com/userfiles/file/423633843.pdfIn PDF document text
    • https://sidexsideaudio.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613bd70d84309---3979398646.pdfIn PDF document text
    • https://tucarrorentacar.co/ckfinder/userfiles/files/surafezob.pdfIn PDF document text
    • https://husvagnsexpo.se/wp-content/plugins/formcraft/file-upload/server/content/files/161389020cda34---69993367094.pdfIn PDF document text
    • https://profipreklady.cz/www/ckfinder/userfiles/files/53929463448.pdfIn PDF document text
    • http://geometracosentino.com/userfiles/files/65937348363.pdfIn PDF document text
    • https://herfection.herfection.tw/upload/ckfinder_temp/files/20210904181613.pdfIn PDF document text
    • http://xahscw.com/userfiles/file/zowapetof.pdfIn PDF document text
    • https://groupekheidri.com/ckfinder/userfiles/files/jipimigixoxuj.pdfIn PDF document text
    • http://basyapiemlak.com/yukleme_klasoru/userfiles/file/23210534656.pdfIn PDF document text
    • http://umffz21.ru/admin/ckfinder/userfiles/files/40267741426.pdfIn PDF document text
    • http://joeun-it.com/userData/board/file/44735757066.pdfIn PDF document text
    • https://scalper.ir/data/files/file/sisuzim.pdfIn PDF document text
    • http://quiltingacademy.info/fckeditor/userfiles/file/xozavolud.pdfIn PDF document text
    • http://stowarzyszeniemalyksiaze.eu/img/upload/files/boludetotikafutatodezaw.pdfIn PDF document text
    • http://w.scenekunstskolen-efteruddannelsen.dk/ckfinder/userfiles/files/33093045632.pdfIn PDF document text
    • http://eyela.kr/uploadfile/fckeditor/file/nibogijekifex.pdfIn PDF document text
    • http://www.anieliasfx.com/uploads/textareas/file/tabijap.pdfIn PDF document text
    • https://www.grandeprairie.org/wp-content/plugins/formcraft/file-upload/server/content/files/1613bd79d874b1---71537478871.pdfIn PDF document text
    • http://ersatzmonitor.de/userfiles/file/godivedabuzimejajamogir.pdfIn PDF document text
    • https://www.saenger-ohg.de/wp-content/plugins/formcraft/file-upload/server/content/files/16130e72bd8322---jalijajubonez.pdfIn PDF document text
    • http://vaonhaphatphap.com/images/uploads/files/madokijodagibudumoxokub.pdfIn PDF document text
    • https://beruanglucu.com/contents/files/pakewasunabi.pdfIn PDF document text
    • https://ladulceseguros.ar/noticias/fckeditor/file/gabetetoju.pdfIn PDF document text
    • https://hoanghaie.com/Images_upload/files/22570260475.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/ngfLrbzwjls/uplcv?utm_term=hokusai+audio+editor+androidPDF 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_off0000bd6c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBD6C 18192 bytes
SHA-256: a84fcbf5fa443030755db4dcb4d893348867673462ed8ca69e412a50e443e59d
font_01_sfnt_off0000ed75.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED75 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001058c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1058C 10380 bytes
SHA-256: 1738669727e06a73197cda9178926cbb4071393f3f2dd65fcdf934403e268f0a