Malicious PDF — malware analysis report

Static analysis result for SHA-256 91f9743356533be0…

MALICIOUS

PDF

90.8 KB Created: 2021-06-25 12:53:33 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-13
MD5: 5d28aa632d0a29e1cff47bc132077736 SHA-1: 0411c480469e94d18e132bc968a531aa185f7603 SHA-256: 91f9743356533be0131a6c0dbca2d9ea75a60cb37b6453f49a2120b8b8184530
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous links pointing to compromised WordPress sites, suggesting a link farm designed to host malicious files. The ML classifier and ClamAV detection strongly indicate malicious intent, likely related to phishing or malware distribution. Although no scripts were directly extracted, the structure and URL findings point to a downloader or phishing lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

Heuristics 7

  • 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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://vernadoc.com/wp-content/plugins/super-forms/uploads/php/files/4e747ccb5674c57a066e9bc87904468a/28523589564.pdf In PDF document text
    • https://leavereview.com/customerinterview/ckfinder/userfiles/files/9902932974.pdfIn PDF document text
    • http://www.ponderosafestival.com/wp-content/plugins/formcraft/file-upload/server/content/files/160861e4583333---xuvokadem.pdfIn PDF document text
    • http://www.idenet.net/wp-content/plugins/formcraft/file-upload/server/content/files/16081b7665a0e6---39484893977.pdfIn PDF document text
    • http://yossy.biz/userfiles/file/weduvuzomitumunuleledu.pdfIn PDF document text
    • http://thm-holding.ru/wp-content/plugins/super-forms/uploads/php/files/8a8a7cb12e83d2a1c02a6a36e1570c0b/33450150306.pdfIn PDF document text
    • https://www.isgs.org/wp-content/plugins/super-forms/uploads/php/files/fe736e05e6b66d8be35faf932c6dfe75/26609356997.pdfIn PDF document text
    • http://kiemtoanhaiphong.vn/upload/files/xotigowona.pdfIn PDF document text
    • https://ewms.vn/wp-content/plugins/super-forms/uploads/php/files/1g2qmo8uehlls5ovl8obbehi0e/95518185704.pdfIn PDF document text
    • http://rethabise.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/160b9e33b7d1ad---bizivovitipeva.pdfIn PDF document text
    • https://www.chartsunlimited.com.ph/wp-content/plugins/formcraft/file-upload/server/content/files/160d3cdff2ead2---36817411473.pdfIn PDF document text
    • https://www.harnoordesigns.com/wp-content/plugins/super-forms/uploads/php/files/qfj62gmo16ec8h2tghnc3u8v26/57926365977.pdfIn PDF document text
    • https://centrosteadycam.it/wp-content/plugins/super-forms/uploads/php/files/4388781cfdd80819f441cc07cf0ea76d/71735648067.pdfIn PDF document text
    • https://plasy.com/uploads/file/rotuwivizusedup.pdfIn PDF document text
    • https://iominneapolis.com/wp-content/plugins/super-forms/uploads/php/files/4b468c22158a07053244bc2a757c76cd/lolozokoxavixos.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/zMnd8XtcwSM/uplcv?utm_term=simple+photo+collage+maker+online+freePDF 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_off0000fefd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFEFD 17584 bytes
SHA-256: aec6fa82f3d9c4f4f6aa16f588a15ff8170e16aecf27d5ed555d23492401ad60
font_01_sfnt_off00012d34.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12D34 10928 bytes
SHA-256: fa1ec1ab138a0b49f1309d731890461b8b7ea122dfa55ed5ecb357ec773ab829
font_02_sfnt_off00014651.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14651 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1