Malicious PDF — malware analysis report

Static analysis result for SHA-256 8f1a6b1d7211a94b…

MALICIOUS

PDF

73.3 KB Created: 2021-09-25 13:18:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 07f231652d0cf7d0cabeec02a43b63b1 SHA-1: fe0811a2a49b3729fc32e0a56499f3b64f6f3e57 SHA-256: 8f1a6b1d7211a94b3b9b5d8331ec7273fcd06c5a442f6a9011a96820fcd96625
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was identified as malicious by ML classifiers and ClamAV, specifically flagged as a phishing trojan. It contains numerous embedded URLs, many pointing to disposable domains, and is described as a link farm. The presence of PDF_SEO_DISPOSABLE_LINK_FARM heuristic further supports this, indicating a tactic to obscure malicious destinations. No scripts were extracted, but the overall structure and URL distribution strongly suggest a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9915

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://laborke.ru/uplcv?utm_term=nitro+instagram+followers+apk+download
    • http://szyoujin.com/UploadFile/file/20210913201347456.pdf
    • https://www.lipca.com/ckfinder/userfiles/files/49880837581.pdf
    • http://joesservicecenternj.com/userfiles/files/savafoba.pdf
    • http://ferien-in-zahren.de/images/file/84727547455.pdf
    • http://forumts.com/ckfinder/userfiles/files/95510221996.pdf
    • http://citysoupsbellevue.com/uploads/files/7757991081.pdf
    • http://chemtron-vostok.ru/media/file/29148188601.pdf
    • http://strap.sk/uploads/file/jarokegagadum.pdf
    • http://vodova51-53.cz/files/rapimitidixatezikoritor.pdf
    • http://wujipacking.tw/upload/files/povojotexog.pdf
    • http://yh-nutri.com/filespath/files/20210923035158.pdf
    • http://interroadholland.nl/userfiles/file/jejujozekijajatofad.pdf
    • https://f27szerviz.hu/upload/files/megobefu.pdf
    • http://jjkxmy.com/upload/files/202109090325259359.pdf
    • http://www.anclupnapoli.it/userfiles/file/nojisezu.pdf
    • http://jcbcharpentebois.com/ressource/site-image/files/dofiriwodijezalad.pdf
    • http://rucodelniza.ru/userfiles/file/51500084715.pdf
    • https://e-casainteligenta.ro/userfiles/file/zoxagibazovakujikukosego.pdf
    • http://samwha.com/upload/userfiles/file/funofagiruvogewosinutudom.pdf
    • http://eclickapps.in/userfiles/files/49315663655.pdf
    • http://rpsbchamber.org/editorData/file/mapolavelogetuf.pdf
    • https://maturana.cl/upload/file/tozutasemaj.pdf
    • http://www.aportecnica.com/imagenes/editor/file/43324536313.pdf
    • http://coreaad.com/DreamDataUpload/file/2354379631.pdf
    • http://greenmodels.ru/uploads/files/85662473838.pdf
    • http://www.afamaresme.org/wp-content/plugins/formcraft/file-upload/server/content/files/16142f786697cb---69391799641.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000b64a.bin
9839b23c9d37579ca2f1aa72183b521e0092af584a9704be361f7dc4f1fa99bb		 pdf-font-stream PDF embedded font (sfnt) at offset 0xB64A 10996 bytes
font_01_sfnt_off0000cfb9.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1		 pdf-font-stream PDF embedded font (sfnt) at offset 0xCFB9 16792 bytes
font_02_sfnt_off0000e7cb.bin
a34fcbd9369a95d0164b2cd3f7c26e144e606f6279dd7b03ce50a6cf8161a718		 pdf-font-stream PDF embedded font (sfnt) at offset 0xE7CB 17680 bytes

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