Malicious PDF — malware analysis report

Static analysis result for SHA-256 81ba97c4a20c064b…

MALICIOUS

PDF

74.7 KB Created: 2021-09-09 11:32:35 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 56cb91cf44389ad880997b3e30135157 SHA-1: 7a6c6f10fbbd399234231857565e33cd313c632a SHA-256: 81ba97c4a20c064bacf4e7a1cc6064fee4f8c54b07a82468e201e1020dd67a79
156 Risk Score

Malware Insights

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

The sample is identified as malicious by ML classifiers and ClamAV, flagging it as a phishing trojan. It functions as a link farm, with numerous URLs pointing to external resources, many hosted on compromised or disposable domains. While no scripts were explicitly extracted, the PDF structure and the nature of the URLs suggest an attempt to lure users to malicious sites, potentially for credential harvesting or further malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9947

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 http://noithatphathuy.com/Images_upload/files/kapefuxodurifunure.pdf In PDF document text
    • http://iscelenie.info/files/file/97207628968.pdfIn PDF document text
    • http://4darchitecture.org/img/all/vomadefujolenugabafug.pdfIn PDF document text
    • http://wedding-box100.com/uploads/files/202109021518097807.pdfIn PDF document text
    • http://mariopresto.pl/userfiles/file/87116485021.pdfIn PDF document text
    • http://deurenhanger.nl/userfiles/file/gaxafabibeja.pdfIn PDF document text
    • https://salondumariagededijon.com/userfiles/file/35842117843.pdfIn PDF document text
    • https://thriveelearning.com/wp-content/plugins/super-forms/uploads/php/files/1c9835bd7a7dec60b57de8c88ce08c46/80200883803.pdfIn PDF document text
    • http://www.mustwalge.ee/data/content/files/89291318956.pdfIn PDF document text
    • http://onthebroadway.com/CPD/adminpanel/upload/file/kovaj.pdfIn PDF document text
    • https://0800-707-808.com/upload/ckfinder_temp/files/20210906130315.pdfIn PDF document text
    • http://elsped.hu/files/file/4370031693.pdfIn PDF document text
    • https://o-dance.com/upload/files/42645807533.pdfIn PDF document text
    • http://www.louthadventures.ie/wp-content/plugins/formcraft/file-upload/server/content/files/161301105a68d0---10787357819.pdfIn PDF document text
    • http://oxigensupplies.com/shipinc/userfiles/files/28669916452.pdfIn PDF document text
    • https://drinkpoint.com/uploads/files/filizowis.pdfIn PDF document text
    • http://studiocinti.eu/userfiles/files/xokakulusaxum.pdfIn PDF document text
    • http://roseeskin.com/userfiles/file/20210903233431.pdfIn PDF document text
    • https://alpinashop.rudy-ra.com/files/pupesivuwiserazedogozop.pdfIn PDF document text
    • http://www.bargiel.com.pl/ckfinder/userfiles/files/35717985398.pdfIn PDF document text
    • http://vhktn.at/images/content/files/81179426010.pdfIn PDF document text
    • https://hoakhanh.vn/uploads/image/files/26599016076.pdfIn PDF document text
    • http://clearlakesd.org/wp-content/plugins/formcraft/file-upload/server/content/files/161320082190ce---38989209354.pdfIn PDF document text
    • http://halongbaycruises.org/upload/files/gefijume.pdfIn PDF document text
    • http://rnralpha.cz/res/file/76083882816.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3CAf4wW3hvY/uplcv?utm_term=google+earth+para+celular+androidPDF 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_off0000be84.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBE84 10764 bytes
SHA-256: 46809f8271cb023dd1d8ffe67d8602fd1eff9337ba4c45fca25fc207c2755114
font_01_sfnt_off0000d703.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD703 17712 bytes
SHA-256: e52bf13d9ad51c32fa45983585479da0358ee247eb161a70a11d73a5dbee2f29
font_02_sfnt_off0001051e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1051E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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