Malicious PDF — malware analysis report

Static analysis result for SHA-256 81b91d0cdb9b6cfa…

MALICIOUS

PDF

80.1 KB Created: 2021-09-09 13:43:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: a479399e2b8e54ef08598c2daa784f7d SHA-1: 309d168eb8dc3dd8a9e6b44e8b88ea067c00fda8 SHA-256: 81b91d0cdb9b6cfa76ad810f04d4a1006f0648023583821b77545e9929d023f2
204 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1190 Exploit Public-Facing Application

This PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. The 'SE_MFA_LURE' heuristic strongly suggests the document is designed to phish for credentials or abuse multi-factor authentication. The presence of embedded JavaScript and numerous external links, some pointing to compromised CMS uploads, further supports the attack pattern of luring users into a credential harvesting scheme, potentially exploiting public-facing applications.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 8

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • MFA / one-time-code harvesting lure high SE_MFA_LURE
    Document asks for a one-time code, authenticator approval, or MFA confirmation — consistent with credential phishing kits that steal session tokens or abuse multi-factor authentication
  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://thefertilizergranulator.com/d/files/64587446160.pdf In PDF document text
    • http://remaining-mc.de/userfiles/file/nikarufimefuligudeg.pdfIn PDF document text
    • http://telekommarketing.com/firme_data/files/17710032713.pdfIn PDF document text
    • https://learningsolution.ca/userfiles/files/86268806726.pdfIn PDF document text
    • http://uptownchantilly.com/uploads/files/wurelusoxez.pdfIn PDF document text
    • https://abzesolar.com/uploads/files/vapukotefeduzuluvovuz.pdfIn PDF document text
    • https://gitteszoneklinik.dk/ckfinder/userfiles/files/42650475676.pdfIn PDF document text
    • http://artdental.hu/editor_up/17135577073.pdfIn PDF document text
    • http://doks-films.com/pcms/content/file/88752011862.pdfIn PDF document text
    • http://wlpp.net/images/blog/file/4445762416.pdfIn PDF document text
    • https://marblo.marblobaths.ph/app/webroot/img/files/51056792448.pdfIn PDF document text
    • https://imapcb.org/wp-content/plugins/super-forms/uploads/php/files/b81a5c0423836c9678b7c06b54ee7040/30532589230.pdfIn PDF document text
    • https://bestmiamiturf.com/wp-content/plugins/super-forms/uploads/php/files/07c3dc48e122d2c19f076908e2d24c9c/33873837339.pdfIn PDF document text
    • https://wacee.net/wp-content/plugins/formcraft/file-upload/server/content/files/161355d41bf6d9---82670282513.pdfIn PDF document text
    • http://defhjdrjioo.friend-match.com/upload/files/detuduj.pdfIn PDF document text
    • http://indemo.pl/Image/files/ziwasiwoji.pdfIn PDF document text
    • http://bumsnab.ru/uploads/files/zixizesavakud.pdfIn PDF document text
    • http://lutechmed.com/Images_upload/files/97506891605.pdfIn PDF document text
    • http://beganijewellers.com/ckeditor/ckfinder/userfiles/files/35641893325.pdfIn PDF document text
    • https://euroroma-bg.org/files/file/zomuxubavol.pdfIn PDF document text
    • http://ifaistos.reality.gr/~triantaf/images/file/61722296446.pdfIn PDF document text
    • https://divorcioconsensual.com.br/wp-content/plugins/super-forms/uploads/php/files/4aafdd00f75139259a29e4b3fa9c2eb2/laburopixutowukoluni.pdfIn PDF document text
    • https://pergamine.com/ckfinder/userfiles/files/25066763995.pdfIn PDF document text
    • http://www.fattyweng.com.sg/wp-content/plugins/formcraft/file-upload/server/content/files/16135f617526d0---95382178172.pdfIn PDF document text
    • https://www.fibertech1.com/my_content/js/ckfinder/userfiles/files/nefesawolanuxuvabije.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3vuEKuznOb8/uplcv?utm_term=nav+score+apkPDF 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_off0000d774.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD774 10164 bytes
SHA-256: 58d5c5480bbdc0769ce8235ae47d4c92a9cab02337bc4b143140e9876840d8c1
font_01_sfnt_off0000ee62.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEE62 17112 bytes
SHA-256: 34fae5fb2a5c287ed24a092161810f49df4341e1a29b8b8e9be5a8e77d336470
font_02_sfnt_off00011aa9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11AA9 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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