Malicious PDF — malware analysis report

Static analysis result for SHA-256 81547446f37c52bc…

MALICIOUS

PDF

69.1 KB Created: 2021-08-24 21:28:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: a097310d44e850e93ec588de83a12abb SHA-1: f471c92db1d06b86b0aaa7efcaee16572e932077 SHA-256: 81547446f37c52bcfeb53440dd956f6236e2d9acb29fea67c3902d0ddfd704bf
154 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1055.012 Process Injection

The PDF file contains numerous external links, many of which point to compromised WordPress sites and disposable hosting. The ML classifier and ClamAV detection strongly indicate malicious intent, likely phishing or malware distribution. The document body is heavily obfuscated and unreadable, providing no direct clues to its purpose beyond the heuristic findings.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9907

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
  • 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
  • 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.mobytec.com.br/mobytec/wp-content/plugins/formcraft/file-upload/server/content/files/1608e89198b54d---xoxakenufisofasijuwojoxad.pdf In PDF document text
    • https://gikguamerica.com/userfiles/file/wasuv.pdfIn PDF document text
    • https://www.smartfutureexpo.com/ckfinder/userfiles/files/58146612411.pdfIn PDF document text
    • https://yucekalipmakina.com/tsrm1/img/userfiles/file/71407529011.pdfIn PDF document text
    • http://studioagronomoserragiotto.eu/userfiles/files/84798983666.pdfIn PDF document text
    • http://www.auditsi.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609ccd6f12167---nifiji.pdfIn PDF document text
    • https://dpengineers.info/admin/userfiles/file/vaxibazafovakajulit.pdfIn PDF document text
    • http://asupuro.com/upload/save_image/files/wefanofazuxosevi.pdfIn PDF document text
    • http://theopenhouseclub.com/wp-content/plugins/super-forms/uploads/php/files/6444a79fd773b1ce1a047e70ce9d8871/75120713540.pdfIn PDF document text
    • http://www.ambredore.com/wp-content/plugins/formcraft/file-upload/server/content/files/16072072389402---vutuxoxomabonaxoz.pdfIn PDF document text
    • https://bywuf.org/upload/editor/files/badozomivonomifisival.pdfIn PDF document text
    • http://soldresold.com/Shradhdha-Mehra/soldresold/final/ckeditorimage/files/87163184266.pdfIn PDF document text
    • http://kowel.com/ckfinder/userfiles/files/1624279881.pdfIn PDF document text
    • http://www.agrosystem.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/160705c26a68c3---gigezo.pdfIn PDF document text
    • https://fastcomputer.vn/wp-content/plugins/super-forms/uploads/php/files/d9c976771b5c4572843a888f25a3f373/44205404004.pdfIn PDF document text
    • http://ddservice-bmw.pl/userfiles/file/zivikadizovupi.pdfIn PDF document text
    • http://nnk.gr/wp-content/plugins/formcraft/file-upload/server/content/files/160c293d3ccc4a---kaxum.pdfIn PDF document text
    • http://mastrodibaglio.it/userfiles/files/vudixozuk.pdfIn PDF document text
    • https://vgi-vn.vn/app/webroot/img/files/gekexisilesufu.pdfIn PDF document text
    • https://salvamontbihor.ro/app/webroot/files/userfiles/files/wutigizewazojanugem.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/Om9ozkHLxGw/uplcv?utm_term=dirty+words+starting+with+aPDF link annotation
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000de61.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDE61 17116 bytes
SHA-256: 7156b3e9e788102ab19a92fcff9f82665a31c261efb5e94f87534119cd94c9dd

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