Malicious PDF — malware analysis report

Static analysis result for SHA-256 ae721921da1e281e…

MALICIOUS

PDF

81.2 KB Created: 2021-09-15 15:48:43 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: d4a6d7dd37300a20ab380d617e8f737e SHA-1: a3a15b1f85b1185566621531b0ba2900cd8be1a5 SHA-256: ae721921da1e281e7abed420e09aeefa99f4b244014bdafd65b0cb700b134ff4
156 Risk Score

Malware Insights

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

The sample was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics identified it as a link farm, with many URLs pointing to compromised CMS uploads and disposable hosting, suggesting a phishing or SEO poisoning campaign. The document body was unreadable, but the presence of numerous external URIs strongly supports the link farm attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

Heuristics 6

  • 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.
  • 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://cructi.ru/uplcv?utm_term=doraemon+virtual+pubg PDF link annotation
    • http://lapempi.nl/ckfinder/userfiles/files/27823204335.pdfIn PDF document text
    • https://luxurytravel-show.com/wp-content/plugins/super-forms/uploads/php/files/78511e76db373bf6d664b4a0c3696f95/nexogiwu.pdfIn PDF document text
    • https://officialbacknumber.org/editor_up/vezivebenis.pdfIn PDF document text
    • http://www.unidacardoso.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1613384bf93164---kowulinigerelu.pdfIn PDF document text
    • http://explosivedevices.ru/media/file/japozow.pdfIn PDF document text
    • http://kraljicabih.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613cf344c91a9---99067004558.pdfIn PDF document text
    • http://www.kotolantopeni.cz/files/97523730324.pdfIn PDF document text
    • https://godahoian.com/app/webroot/upload/files/tixebanek.pdfIn PDF document text
    • http://rkenterprisesonline.com/FCKeditor/file/61812556607.pdfIn PDF document text
    • http://www.hkqi.com/wp-content/plugins/formcraft/file-upload/server/content/files/161408c3844c8e---50836422997.pdfIn PDF document text
    • http://abworder.com/uploads/files/vivewer.pdfIn PDF document text
    • https://pleasanton.com/wysiwygfiles/file/91108272635.pdfIn PDF document text
    • https://djhelaly.com/wp-content/plugins/super-forms/uploads/php/files/2c10fbfd3b01ee30fae87ed1abc00139/17176683422.pdfIn PDF document text
    • http://boldogelet.hu/media/makasaku.pdfIn PDF document text
    • http://e-skala.pl/userfiles/file/lebasovavofuwulazogugumaw.pdfIn PDF document text
    • https://stmpallet.com/ckfinder/userfiles/files/64171989658.pdfIn PDF document text
    • https://actsonics.com/uploads/files/202109110924376670.pdfIn PDF document text
    • https://dunakanyarfesto.hu/ckfinder/userfiles/files/10786636450.pdfIn PDF document text
    • http://klusjesindex.nl/images/uploads/bigizutakesobabamidazif.pdfIn PDF document text
    • http://vmkmsz.hu/userfiles/file/sunakorewolofuxube.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://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_off0000d612.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD612 19004 bytes
SHA-256: 69c4b1446074bff0725defcbce536e80dbb706613d92799b1b9d987883227e97
font_01_sfnt_off000106f9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x106F9 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011f10.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11F10 10732 bytes
SHA-256: 418d2f1ced2c5bcda6c8b119c36bf11330015c97a4a34b1edf41c87d4e1f8c9e