Malicious PDF — malware analysis report

Static analysis result for SHA-256 d21c5259a200ff77…

MALICIOUS

PDF

90.6 KB Created: 2021-08-25 09:59:21 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: ad35b36a76a979fc0a3befc7f19eca2e SHA-1: f354b2b4d9236d3fdf12578d639e8082f1911f4e SHA-256: d21c5259a200ff77da8ec60cc353963559b4ba1062f9cc67107f4a919386bbaf
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with many embedded URLs pointing to potentially compromised or disposable hosting. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather to host links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9985

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://muachungbaohiem.com/uploads/userfiles/file/zilejixugixovav.pdf In PDF document text
    • http://fujiya-burbank.com/uploads/files/tebagegugikinutoweloro.pdfIn PDF document text
    • http://global-insurance-broker.de/downloads/41910502450.pdfIn PDF document text
    • https://freedomtampons.com/wp-content/plugins/super-forms/uploads/php/files/f6d0fd338af470cf758136a3c0860b5b/59612697705.pdfIn PDF document text
    • https://rffsev.ru/wp-content/plugins/super-forms/uploads/php/files/e6ec2333f587d2f2c3bbd2badfcf67c4/56058889550.pdfIn PDF document text
    • https://www.propertyfilevault.com/wp-content/plugins/super-forms/uploads/php/files/157825c632893c8daa2a151c7114c4f5/furajebijovuvunoromud.pdfIn PDF document text
    • https://yildizwebpaket.com/calisma2/files/uploads/1575212093.pdfIn PDF document text
    • http://bjdfszwy.com/filespath/files/20210824190157.pdfIn PDF document text
    • https://schmitz.cz/res/file/3580345537.pdfIn PDF document text
    • http://marketherballize.com/ckfinder/userfiles/files/29654172520.pdfIn PDF document text
    • https://www.jemelectric.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608d7817437fa---bigonatubeka.pdfIn PDF document text
    • https://www.hospedeagora.com.br/wp-content/plugins/super-forms/uploads/php/files/953l7a9ddlhbovqoabr949k8rv/javosokanidarubo.pdfIn PDF document text
    • https://fizjolech.pl/userfiles/file/nunepujema.pdfIn PDF document text
    • http://connect-event.fr/ckfinder/userfiles/files/safetidavarebizetiluladom.pdfIn PDF document text
    • http://cwesp.biz/upload/file/gabajejojewujava.pdfIn PDF document text
    • https://pasarantogel2.com/contents/files/wonelerumu.pdfIn PDF document text
    • http://aarogyamedico.com/userfiles/file/19643866014.pdfIn PDF document text
    • https://2greenchicks.com/wp-content/plugins/super-forms/uploads/php/files/8c05ecc84aa8b03b4495d7954b19b597/vuzituzo.pdfIn PDF document text
    • https://www.sidertest.it/wp-content/plugins/formcraft/file-upload/server/content/files/1609ee112281c0---8648441473.pdfIn PDF document text
    • http://www.magicapro.it/wp-content/plugins/formcraft/file-upload/server/content/files/1607e5f4b0e40d---1526227399.pdfIn PDF document text
    • http://www.medical-psychology.gr/wp-content/plugins/formcraft/file-upload/server/content/files/160c5cec42bee4---vokadobugizazubafusit.pdfIn PDF document text
    • http://short-story.ru/upload/file/nonebereba.pdfIn PDF document text
    • https://www.helmmsp.ca/wp-content/plugins/super-forms/uploads/php/files/fea52b92b748268a17e9472a074095bb/roledeguxuvomokagetenura.pdfIn PDF document text
    • https://metal-et-verre.ch/ckfinder/userfiles/files/95571196021.pdfIn PDF document text
    • https://www.mii.net/wp-content/plugins/super-forms/uploads/php/files/577646789367fdfa1bf72d35d39ac0b5/mexixinidomov.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/S30rS-6n6vg/uplcv?utm_term=acid+properties+in+dbms+with+examples+pdfPDF 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_off0000fc45.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFC45 11192 bytes
SHA-256: b42101036dd7878e4fd0d4cab50f0a302fae4633ac3e1dfede831b097bc76ee3
font_01_sfnt_off00011620.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11620 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012e32.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12E32 17328 bytes
SHA-256: 51cdede1c4526a4eda465cde561498e995cbf650c4c7845110213c17f6a05974