Malicious PDF — malware analysis report

Static analysis result for SHA-256 b99f88b2e8499867…

MALICIOUS

PDF

84.8 KB Created: 2021-03-16 18:02:03 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-21
MD5: 25ee20c386805d93b6a07912323e177d SHA-1: 765c89deb33793bfc65606c684a90139dba38eef SHA-256: b99f88b2e84998671f94634a788ca86e661a61c3869f6ee3944aa55776aa9d19
186 Risk Score

Malware Insights

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

The PDF contains numerous external links, many hosted on disposable domains, suggesting a link farm or phishing operation. The ClamAV detection and ML classifier strongly indicate malicious intent, likely to redirect users to malicious sites. While no scripts were explicitly extracted, the PDF structure and heuristic firings point towards a malicious document designed to exploit users via external links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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
  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • 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://mezovuduw.ru/strik?utm_term=magic+tree+house+book+17+quiz PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4371020/normal_604a4abc78909.pdfIn PDF document text
    • http://sujabupinoda.scienceontheweb.net/xajabanulaxuzulupusamela.pdfIn PDF document text
    • https://vowizata.weebly.com/uploads/1/3/1/8/131856430/rupimotatifafap-negobanifewix-rinimagam.pdfIn PDF document text
    • http://wazixusazajafem.22web.org/vekupuputuzililexem.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4469104/normal_5fddda770a93e.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4448551/normal_601f58c2ef3cf.pdfIn PDF document text
    • https://nogonosexenepe.weebly.com/uploads/1/3/4/6/134674491/jezebinutow-guzojesevidug.pdfIn PDF document text
    • https://rixotojar.weebly.com/uploads/1/3/0/9/130969533/b94d8c84aa82aa.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4457272/normal_602aaddac105e.pdfIn PDF document text
    • http://gexomafe.mypressonline.com/papelito_calligraphy_workbook.pdfIn PDF document text
    • http://fisidunetozusi.iblogger.org/geographic_information_system_l_g.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://uploads.strikinglycdn.com/files/8c0d7141-60b5-4128-8d32-56535e725ccf/33528610359.pdfIn PDF document text
    • http://lumosaneja.onlinewebshop.net/42567377605.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/44c1d6b8-6860-439a-8e34-b57d90eaac70/73100879393.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/16333783-26fe-4ed2-aeee-d199d1b5a45f/kajiwerolozinonusov.pdfIn PDF document text
    • http://xejarejunap.rf.gd/wonotudotekitam.pdfIn PDF document text
    • http://bodasubosixo.rf.gd/james_and_the_giant_peach_full_book_summary.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/be999a51-827e-45a7-96bf-1f4be4d54e98/what_do_the_flashing_lights_on_my_router_mean.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/4b74436c-1531-43ff-8908-300b00e60996/dabujoserige.pdfIn 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_off00010bf5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10BF5 5548 bytes
SHA-256: 51222df66b46e5e0f26b74b4e653ad6d0558cf4ada6ff6785c1d4fc06c230f81
font_01_sfnt_off00011eee.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11EEE 11548 bytes
SHA-256: 1df97e857d97453375d9634824b614fd5b18f456c037b3112d74c3541f89da73