Malicious PDF — malware analysis report

Static analysis result for SHA-256 6b15dc73913ff8f0…

MALICIOUS

PDF

81.3 KB Created: 2021-06-13 17:19:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-27
MD5: d9f143aea02e3fdf82a210b7bae3c309 SHA-1: 3f4f9f0dec67be0766fab531a4bd38c00bbecc31 SHA-256: 6b15dc73913ff8f0efb686d78b5bce37c03cb460769eee40fe349adeebcecd3b
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF document contains numerous links to external websites, many of which appear to be hosted on compromised WordPress installations or disposable domains, suggesting a link farm or phishing lure. The ML classifier and ClamAV detection strongly indicate malicious intent. The document body text, though heavily obfuscated, contains keywords related to 'worksheet answers', likely serving as a pretext to drive users to malicious URLs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://infrive.ru/uplcv?utm_term=3x3+system+of+equations+worksheet+answers PDF link annotation
    • http://capital96.com/userfiles/file/dunapenivesulepo.pdfIn PDF document text
    • https://agrilaui.com/userfiles/file/gitujivuxizukumususil.pdfIn PDF document text
    • http://modellszerviz.hu/userfiles/file/68081182492.pdfIn PDF document text
    • https://www.nestroots.com/wp-content/plugins/super-forms/uploads/php/files/1c7rugddja15d91hjmlj8h4bd7/zerujamogituvireg.pdfIn PDF document text
    • http://clinicacomciencia.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160720b063ee70---suvumubinisoxoked.pdfIn PDF document text
    • https://truck-diagnostic.ru/wp-content/plugins/super-forms/uploads/php/files/c11cee3f73e83c4cf6837d4676a25edd/68767182876.pdfIn PDF document text
    • https://luminex.pl/upload/file/1648360119.pdfIn PDF document text
    • https://www.lowdoc-loans.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160c374bcb06f8---niwutujowo.pdfIn PDF document text
    • http://unseenadventure.com/userfiles/file/dubifijizakixukuluvakamo.pdfIn PDF document text
    • https://yuss.it/file/lopur.pdfIn PDF document text
    • https://webgirls-studio.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b9d1fb1a7f7---58123526319.pdfIn PDF document text
    • http://www.scmphotography.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16077bc8365a10---39486597431.pdfIn PDF document text
    • https://theshairpodcast.com/wp-content/plugins/super-forms/uploads/php/files/28a56d496b1f90ac4b73eee1aee11f94/velelezojoji.pdfIn PDF document text
    • http://apartmaji-zunicmile.com/uporabnik/file/jevozuvifon.pdfIn PDF document text
    • http://chicagohalo.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609f7e1dcea0b---4928019500.pdfIn PDF document text
    • https://www.hungarianassociation.com/wp-content/plugins/formcraft/file-upload/server/content/files/16073d4cda4c38---buwizewukodusitok.pdfIn PDF document text
    • https://www.d-table.com/wp-content/plugins/super-forms/uploads/php/files/9a51fa74a2d383feb0e012a05a1f0839/vudux.pdfIn PDF document text
    • http://socialbomjesus.org.br/wp-content/plugins/formcraft/file-upload/server/content/files/160b16f145191c---83012307514.pdfIn PDF document text
    • http://www.k-24.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609afc488952b---rikiwotozerurim.pdfIn PDF document text
    • https://fablab808.com/nbloom/fckuploads/file/27911347626.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.daltonmaag.com/In 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f1f0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF1F0 5380 bytes
SHA-256: c6f6967a5930e16b4e967c22c65bea92ab99e5f7e43983b86941799eb0f98be5
font_01_sfnt_off00010426.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10426 10932 bytes
SHA-256: 39d0c36587bee11bafb94308eeefae7cf475cd077fe7b7f3ff7ec254a3a92b7f
font_02_sfnt_off00012989.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12989 4324 bytes
SHA-256: 1158d95dac44631f497756703988ba3645251422e7ff0015d3fca430225e7c3e

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