Malicious PDF — malware analysis report

Static analysis result for SHA-256 a8aa1082d2baf6fb…

MALICIOUS

PDF

85.0 KB Created: 2021-09-10 13:53:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: a3b5fc417a0e8d924846925446b55387 SHA-1: 8ce0afe48989aa3723ccb1cbdc498664421c6b91 SHA-256: a8aa1082d2baf6fb0f2435f9b2cbe248673c5098ce278d949db9c22e9806abbd
156 Risk Score

Malware Insights

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

The PDF file was flagged by multiple heuristics as malicious, including a critical ClamAV detection and an ML classifier. It contains a link farm pointing to compromised WordPress uploads and other disposable hosting, suggesting an attempt to distribute malicious content or phish users. The presence of numerous embedded URLs further supports this attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

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://hoakhanh.vn/uploads/image/files/24640283394.pdf In PDF document text
    • https://eirai.org/editor/ckfinder/userfiles/files/60677681727.pdfIn PDF document text
    • https://cbolean.com/wp-content/plugins/super-forms/uploads/php/files/16e38569f4a7a221683a772784f3d090/79145297724.pdfIn PDF document text
    • http://dabaizhongxue.com/upload_fck/file/2021-9-1/20210901094954381120.pdfIn PDF document text
    • https://studiecarriere.it/uploads/file/64730216845.pdfIn PDF document text
    • http://freemansphotography.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613b1bd78cc93---67829946636.pdfIn PDF document text
    • http://somsit.com/ckfinder/userfiles/files/menovedewutebuwimokiw.pdfIn PDF document text
    • http://nontaromclinic.com/ckfinder/userfiles/files/2876867719.pdfIn PDF document text
    • https://braintreeclinics.com/app/webroot/img/files/64702901750.pdfIn PDF document text
    • https://mobiligennari.com/userfiles/file/69959401090.pdfIn PDF document text
    • http://strelnicebudejovice.cz/userfiles/file/70726896009.pdfIn PDF document text
    • http://argentum.com/wp-content/plugins/super-forms/uploads/php/files/aqkn7a4oc5eta02cn1k9jhl3rr/fuleresobamuduru.pdfIn PDF document text
    • http://sten.kr/club/data/userfiles/file/20210903113024.pdfIn PDF document text
    • https://plewmal-d.com/Uploads/files/lofifupapalijutapite.pdfIn PDF document text
    • http://firmykominkowe.pl/Obrazki/edytor/file/30202133067.pdfIn PDF document text
    • http://udokutscher.de/gfx/userfiles/files/48761272384.pdfIn PDF document text
    • http://getampedmag.com/ckfinder/userfiles/files/tulisa.pdfIn PDF document text
    • http://contua.org/userfiles/file/zoxidagusukilejiponom.pdfIn PDF document text
    • https://uzsienis.cvzona.lt/resources/img/files/15588278206.pdfIn PDF document text
    • http://www.ochoadentalcare.com/tacgestorcontenidos_ochoa/documentos/file/In PDF document text
    • http://velapower.com/glwh/UploadFile/file/2021090913072873499.pdfIn PDF document text
    • http://dorp.pl/userfiles/files/75844730592.pdfIn PDF document text
    • https://digicpictures.com/downloads/savuvaguzivudanoj.pdfIn PDF document text
    • https://independentmusicleague.com/wp-content/plugins/super-forms/uploads/php/files/83d02272f9c7c0424ed1fb644b617723/32816766792.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/BkSY9tpko7c/uplcv?utm_term=where+is+the+microphone+on+my+android+phonePDF link annotation
    • 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://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e6db.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE6DB 10840 bytes
SHA-256: 3ca4bef5260046344faaf28e797ded4e309655d7e76053a7eb6f60c05d479a13
font_01_sfnt_off0000ffc5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFFC5 17832 bytes
SHA-256: 044bf1ffe00ca527a1548d624623d27f045c7b03af86ceb6d0ec37b23df9d97e
font_02_sfnt_off00012e50.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12E50 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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