Malicious PDF — malware analysis report

Static analysis result for SHA-256 4d71acbad0b19a5a…

MALICIOUS

PDF

73.8 KB Created: 2021-06-13 11:55:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-04
MD5: 26540fedfa658de173d7b9331d4a7970 SHA-1: 8777d1514a55c6c693383d47fd93b8b37dd2c768 SHA-256: 4d71acbad0b19a5a5882e71b6728ec8e7bbe39326b68ecfcdbdcae6abaa833b1
164 Risk Score

Malware Insights

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

This PDF document was flagged as malicious by ClamAV and an ML classifier. The file embeds a large number of external links characteristic of an SEO link farm, many hosted on compromised CMS upload directories and presents a deceptive download button. Specific URLs and indicators for this sample are listed in the indicators section.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9999

Heuristics 7

  • 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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://krisoc.ru/uplcv?utm_term=five+sentences+of+present+perfect+continuous PDF link annotation
    • https://www.yoursurveysurveyors.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160a62a661813f---tenerixotuzasisuxexekug.pdfIn PDF document text
    • http://pavcargo.ru/wp-content/plugins/super-forms/uploads/php/files/d91866bf54e4d8f6725836892722ea89/78339452976.pdfIn PDF document text
    • http://www.suffaheducation.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c1b9caa17c7---58255422056.pdfIn PDF document text
    • http://juniorsmagazine.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608c01834bb6e---nisitan.pdfIn PDF document text
    • http://architects-desk.com/uploadsfile/25499526729.pdfIn PDF document text
    • https://www.ferienhof-schneider.de/wp-content/plugins/formcraft/file-upload/server/content/files/1609e14189f7db---xagetatogupotuvakulodake.pdfIn PDF document text
    • http://www.garriagricola.com/wp-content/plugins/formcraft/file-upload/server/content/files/160978ad5ef74f---bowezolejofo.pdfIn PDF document text
    • http://dossalas.com/wp-content/plugins/super-forms/uploads/php/files/958b8d358c9833b6e22f3e518f0a760c/87363757059.pdfIn PDF document text
    • https://stewsites.com/wp-content/plugins/super-forms/uploads/php/files/ef190ebcbd751aeff62e54c08e00c254/93744671935.pdfIn PDF document text
    • https://ovalpolycoats.com/media/79990470799.pdfIn PDF document text
    • http://ecohost.ru/pics/images/file/59728664368.pdfIn PDF document text
    • https://adiwirawanbali.com/wp-content/plugins/super-forms/uploads/php/files/d966bdfb438899eca075552d543abdb1/70740272433.pdfIn PDF document text
    • http://cetinelektrik.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/160b34db8118c4---63181616673.pdfIn PDF document text
    • http://amandatravel.com/userfiles/file/motetubopijujojiba.pdfIn PDF document text
    • http://www.whirlpool-beachcomber.at/wp-content/plugins/formcraft/file-upload/server/content/files/160b5f5d478397---gajazeziruguruzavulagedep.pdfIn PDF document text
    • http://www.kickcommerce.com/userfiles/file/85440684039.pdfIn PDF document text
    • http://zwickerfoto.hu/_user/file/zuwegimedigolobupikego.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_off0000e2f1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE2F1 4784 bytes
SHA-256: 1606efb6b8ec5038aee80cb9f84d89b714d0fff544f3bf2feb3d2b5db9f58122
font_01_sfnt_off0000f359.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF359 11076 bytes
SHA-256: 46c354675ebf9f510c6e40b5047eabdc060a0618e46b4a3ac9f34879ca68666b