Malicious PDF — malware analysis report

Static analysis result for SHA-256 a4188d3e73e868ff…

MALICIOUS

PDF

77.7 KB Created: 2021-06-10 19:03:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-04
MD5: 18128b3e29f892203081f860d03ff201 SHA-1: 99251a4ca7244aadd939bf7a3ed0ffc7a5392e36 SHA-256: a4188d3e73e868ff0e4a70088beadd38c73775196bcf57cb7c578d31d88bc6d3
236 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link T1059.007 JavaScript

This PDF document was flagged as malicious by ClamAV and an ML classifier. It uses a fake-CAPTCHA lure and a password-protected-archive lure. The file embeds a large number of external links characteristic of an SEO link farm, many hosted on compromised CMS upload directories. Specific URLs and indicators for this sample are listed in the indicators section.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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
  • Fake CAPTCHA / human verification prompt high SE_FAKE_CAPTCHA
    Document displays a fake CAPTCHA or human-verification prompt — used to trick users into running commands or pressing keyboard shortcuts
  • Password-protected archive handoff high SE_PASSWORD_ARCHIVE_LURE
    Document gives password instructions for an archive or attachment — often used to keep payloads encrypted until after gateway scanning
  • 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://coretry.ru/uplcv?utm_term=easy+bypass+apk PDF link annotation
    • http://akcjonariusz.com/UserFiles/file/diwamamodufebuxor.pdfIn PDF document text
    • https://www.modianodesign.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b0ce7beddeb---mijapodiduzoluguzotemixat.pdfIn PDF document text
    • http://yuseigachi.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16080945b2931e---bamopamizunawarurugisine.pdfIn PDF document text
    • http://irina-beha.com/ckfinder/userfiles/files/76149505017.pdfIn PDF document text
    • https://xn-----6kcabagcgfjsxjciriy6alkh6a7aqk.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/bf7a93f9eacb7133c000c3d4d439f744/28801080851.pdfIn PDF document text
    • http://jamoncup.es/wp-content/plugins/formcraft/file-upload/server/content/files/160b4566d44dc3---lidadawolovumavoxa.pdfIn PDF document text
    • https://accesoriosalmayor.com/images/userfiles/file/52874749121.pdfIn PDF document text
    • http://peneleos.pl/userfiles/file/38867281073.pdfIn PDF document text
    • http://www.stratcareerservices.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606fbd42f34b9---tukuzelarojaguletoga.pdfIn PDF document text
    • http://dobryremont.pl/ebobas/portal/app/webroot/img/tmp/file/16205235274397.pdfIn PDF document text
    • https://www.costaverde.it/wp-content/plugins/formcraft/file-upload/server/content/files/160bd35ea90975---nakadiloberorima.pdfIn PDF document text
    • https://vansuloi.com/uploads/userfiles/file/fivatagelakalemusinezome.pdfIn PDF document text
    • http://www.annaleehuber.com/content_files/file/93180382174.pdfIn PDF document text
    • https://jclifeschools.org/wp-content/plugins/super-forms/uploads/php/files/ea88891b3ea6b374e8758806b713a51b/22870685926.pdfIn PDF document text
    • http://www.amedna.com/userfiles/files/xavopezofipowudigitadog.pdfIn PDF document text
    • http://www.movingintofreedom.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607ca38f1b7b4---23974056412.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f107.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF107 4948 bytes
SHA-256: c96a5c47771b9565a80d280eea8b3099b701b51cc3b190c2c10fa7a8a53d9d90
font_01_sfnt_off000101fa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x101FA 11872 bytes
SHA-256: 2cf49b0f74541396d5fa33c7f30beb9f5504d869461e27395ac5c1478441a14b

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