Malicious PDF — malware analysis report

Static analysis result for SHA-256 21dc2f3de9deaa75…

MALICIOUS

PDF

68.7 KB Created: 2021-09-23 07:41:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 917416df0b1a6862a4db90ce77f94840 SHA-1: 13c1b7a5ca470ed1d1eb4f0f09a3d46dd8bbf6b3 SHA-256: 21dc2f3de9deaa75234cf1f7e8a3d8db275d4ff37d781eaf140e74a195b0b27a
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to disposable hosting or compromised CMS upload directories, indicating a link farm designed to redirect users. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware distribution through these links. The PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM heuristic specifically highlights the use of compromised WordPress upload storage.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

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 https://aitalk.vn/upload/files/38139934845.pdf In PDF document text
    • http://gibkrakow.pl/uploads/files/norem.pdfIn PDF document text
    • http://www.bash.cl/media/file/paderiretokofalixape.pdfIn PDF document text
    • https://sedefartphotography.com/resimler/files/genozowaxiritewuxuga.pdfIn PDF document text
    • http://berbun.com/user_img/file/44710119923.pdfIn PDF document text
    • http://www.valathors.com/ckfinder/userfiles/files/8499934594.pdfIn PDF document text
    • http://www.farmaciapenil.es/userfiles/files/50035171217.pdfIn PDF document text
    • https://agsposure.org/wp-content/plugins/super-forms/uploads/php/files/25913a42a278ae386ce2e40b3f445ff8/fujivugawomigerozome.pdfIn PDF document text
    • http://tzsunup.com/upload/77737513734.pdfIn PDF document text
    • http://www.patriarca-batiment.com/ressource/site-image/files/74538926126.pdfIn PDF document text
    • http://formel1vermietung.de/userfiles/file/moxugenelodatedixe.pdfIn PDF document text
    • http://henca.com/files/details/file/25322731947.pdfIn PDF document text
    • https://www.scanworld.se/wp-content/plugins/formcraft/file-upload/server/content/files/16137b56da9a9d---29855110421.pdfIn PDF document text
    • https://www.kiemtoandongnghi.com/public/plugins/ckfinder/userfiles/files/likum.pdfIn PDF document text
    • https://petroblend.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613b76d3eb80a---49679333035.pdfIn PDF document text
    • http://kezheng.net/Upload/file/sokovilupuvuposotil.pdfIn PDF document text
    • http://schodylux.pl/userfiles/file/fitorazaxenakugerilaxewa.pdfIn PDF document text
    • http://ketoanaca.com/uploads/image/files/nabisafalizazuwutimazi.pdfIn PDF document text
    • http://hcbarrett.com/user_area/file/81175709237.pdfIn PDF document text
    • http://unionasset.net/file_upload/spaw_upload/file/20210902010017.pdfIn PDF document text
    • http://frankslawfirm.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/63950186425.pdfIn PDF document text
    • https://www.highlandernepal.com/assets/ckfinder/userfiles/files/kefetoxug.pdfIn PDF document text
    • http://librojuridico.com/aym_images/files/58050816558.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/GLLx1DTH0VQ/uplcv?utm_term=cheat+dls+2019+coinPDF 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_off0000b141.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB141 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000c953.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC953 14256 bytes
SHA-256: f3c6954ceb269461103cbb4df2f436a29ca8fed39f14d439c0d7d57db5884e90
font_02_sfnt_off0000ecc8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xECC8 10860 bytes
SHA-256: b6a68bb1aa86eee21df2cfd37d1dccd6d4d2da8996c6ba05a8975052deaee7f9

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