Malicious PDF — malware analysis report

Static analysis result for SHA-256 8c4e39ffe636180a…

MALICIOUS

PDF

79.3 KB Created: 2021-09-08 09:24:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 30424e1e0098946b4a5247b82ee62bbc SHA-1: f8b4b081050adf52cc7c08eff9753d5110ac841a SHA-256: 8c4e39ffe636180a8c58d9bef5825d4f53a342a1be4da5f37224852e7cb33d4f
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file contains multiple links to external resources, many of which are hosted on compromised WordPress sites, indicating a link farm designed to distribute malware. The ML classifier and ClamAV detection strongly suggest malicious intent. Although no scripts were directly extracted, the PDF structure and heuristic firings point towards a phishing or malware distribution lure, likely using embedded JavaScript to facilitate the download of a second-stage payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

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 https://www.unicodesystems.com/wp-content/plugins/super-forms/uploads/php/files/33ngsnr1efca1vopr3cb0gqq72/18853776998.pdf In PDF document text
    • https://www.finestkindcharter.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606cb4872eab0---dejedoduxubexawixeso.pdfIn PDF document text
    • https://sunwayhk.com/louis/STARKGROUP/ckfinder/userfiles/files/12556937477.pdfIn PDF document text
    • http://nc2e.fr/wp-content/plugins/formcraft/file-upload/server/content/files/1612cc66d184e0---48541299136.pdfIn PDF document text
    • https://alasclub.gr/neuro/ckfinder/userfiles/files/617100594.pdfIn PDF document text
    • http://asja-doll.ru/userfiles/file/97888510781.pdfIn PDF document text
    • http://waterreducer.cn/d/files/59568416284.pdfIn PDF document text
    • https://www.zaantraining.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160838fcb4d50f---nisoxapexoturapivumun.pdfIn PDF document text
    • http://ambulatorioveterinarioscapindandrea.it/userfiles/files/tobinalebalisekobupidujog.pdfIn PDF document text
    • http://disonde.com/filespath/files/20210805135256.pdfIn PDF document text
    • https://siphouse96.com/wp-content/plugins/super-forms/uploads/php/files/552be198ac4e9535ced85f8b416924c3/15623953795.pdfIn PDF document text
    • http://aeskulap24h.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607d31fb3c851---futozifi.pdfIn PDF document text
    • https://pnp-studio.com/fckeditorfiles/file/korepaxemitejokovolojawis.pdfIn PDF document text
    • https://szpital-sulecin.pl/images/fckfiles/file/53935399019.pdfIn PDF document text
    • http://aeskulap24h.de/wp-content/plugins/formcraft/file-upload/server/content/files/160c51546349c0---66674385528.pdfIn PDF document text
    • http://loaamtran.com/files/usersfiles/files/76176894092.pdfIn PDF document text
    • http://lushexperiences.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608b948aba9b1---60377834579.pdfIn PDF document text
    • http://slowjamsundays.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607ac4d393440---dekitelisewemu.pdfIn PDF document text
    • http://etrustmi.com/ckfinder/userfiles/files/welekorijedovixular.pdfIn PDF document text
    • http://associatedreclaimed.com/userfiles/files/dafaloxexikuvaluwuxemaf.pdfIn PDF document text
    • http://www.phonefixcomo.com/wp-content/plugins/formcraft/file-upload/server/content/files/160e511445a052---9416862306.pdfIn PDF document text
    • http://ekonopuntos.com/campannas/file/69152352581.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/1KS0DP0cxss/uplcv?utm_term=2007+toyota+sienna+repair+manual+free+downloadPDF 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_off0000d0bc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD0BC 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000e8d3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE8D3 11152 bytes
SHA-256: e4c7e75307582e2e4524e872e1dd4ecac29cc907cd58095e593b6ddcef2cc952
font_02_sfnt_off0001030d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1030D 16896 bytes
SHA-256: dd3349f4143f8f29fe078cad0f97627b089f7fe3d7320c672c5face40e436125

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