Malicious PDF — malware analysis report

Static analysis result for SHA-256 c5fef23f0b3efde9…

MALICIOUS

PDF

73.3 KB Created: 2021-09-26 00:23:55 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 074f8448791c22bab91ac7eb1a92a3bb SHA-1: b3169f05f44a8a97b3dcb7e0f7765d895332eee1 SHA-256: c5fef23f0b3efde988f58d41357dffb555a6a546baa7b65765037e5000f65477
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ML classifiers and ClamAV, specifically identified as a phishing trojan. It contains numerous embedded URLs, many pointing to PDF files hosted on various domains, suggesting a link farm designed to redirect users. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic further supports this, indicating a tactic to obscure the true malicious destination.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9963

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 http://slkuang.com/v15/Upload/file/2021926511549501.pdf
    • http://loaamtran.com/files/usersfiles/files/pofivofir.pdf
    • http://rcsiprojectracker.com/userfiles/files/51174505053.pdf
    • http://suachuaspa.com/upload/images-content/files/88114400208.pdf
    • https://residenciasanamaro.es/userfiles/files/52593266954.pdf
    • https://leciv.fr/uploads/FCK_files/file/53593125852.pdf
    • https://penal-garazh.ru/files/xefemikedugowapikuza.pdf
    • http://solamsys.com/userData/board/file/kopepupi.pdf
    • http://alburigiott.it/userfiles/files/zepisikuxe.pdf
    • http://inbond-cn.com/userfiles/file/zufemibesomoserot.pdf
    • https://vicotelecom.vn/static/source/images/file/35561317100.pdf
    • https://osakaav.com/userfiles/files/45426605299.pdf
    • http://cnex.cc/images/blog/file/80975492292.pdf
    • http://redigonda.it/userfiles/files/50277387888.pdf
    • http://dekoblickfang.de/userfiles/file/ladogin.pdf
    • https://weekendtripskolkata.com/userfiles/file/47509348901.pdf
    • http://benthanhsgfarm.com/images/uploads/files/bijobuwifetuxopatubim.pdf
    • https://rpdev.org/ckfinder/userfiles/files/lonobuxepive.pdf
    • http://hermanosgolbano.com/admin/fckeditor/editor/filemanager/connectors/phpfile/jisojumabozoforumokujil.pdf
    • https://sausalito.com/wysiwygfiles/file/52450329445.pdf
    • https://bizdrive.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1/161389db662b2e---37374104233.pdf
    • https://expungemyrecordnj.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613559567fa28---xizapudedekudibunero.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/DOqCt-cVA4I/uplcv?utm_term=reduce+picture+size+on+android
    • 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_off0000b7a3.bin
6b2fe1fd8234b3013919ca4dc14abf5526b0c72360cb55eac211bc627c185529		 pdf-font-stream PDF embedded font (sfnt) at offset 0xB7A3 10668 bytes
font_01_sfnt_off0000d03d.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1		 pdf-font-stream PDF embedded font (sfnt) at offset 0xD03D 16792 bytes
font_02_sfnt_off0000e84f.bin
e6290faefa21a6475fb5ccae91c6abe58998a4b4640fb2278621f1650b459485		 pdf-font-stream PDF embedded font (sfnt) at offset 0xE84F 18528 bytes

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