Malicious PDF — malware analysis report

Static analysis result for SHA-256 a4871e8fed1ebc6f…

MALICIOUS

PDF

81.3 KB Created: 2021-09-08 03:07:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: 81f3ab1e7f014d5babcd32872d580bc5 SHA-1: f54a0b085654bca6fa8e0d8281346dd056db1063 SHA-256: a4871e8fed1ebc6fb16e985942d8924bc819296d5e5fc3399aaaa553f3ecfd67
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.001 User Execution: Malicious Link

The PDF contains a large number of embedded links, many pointing to compromised WordPress sites, suggesting a link farm or phishing lure. The ClamAV detection and ML classifier strongly indicate malicious intent, likely related to phishing or malware distribution. No scripts were extracted, and the document body was unreadable, but the heuristic findings are sufficient to assess the attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9955

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://smidgel.ru/uplcv?utm_term=schubert+synthesis+of+inorganic+materials+pdf PDF link annotation
    • http://www.vivelamusica.es/wp-content/plugins/formcraft/file-upload/server/content/files/16080d5c455e44---41219577130.pdfIn PDF document text
    • http://snookerfootball.eu/wp-content/plugins/formcraft/file-upload/server/content/files/160a7f0028f0fd---30260670348.pdfIn PDF document text
    • http://sergey-yushkov.com/pict/file/12580223477.pdfIn PDF document text
    • http://www.whirlpool-beachcomber.at/wp-content/plugins/formcraft/file-upload/server/content/files/16137c4c6d6cb6---rumiduledep.pdfIn PDF document text
    • http://brothersaluminium.com.np/wp-content/plugins/formcraft/file-upload/server/content/files/160b9133af0045---rekewuzeveladozatuzexufi.pdfIn PDF document text
    • http://jun-travel.com/userfiles/file/72705304365.pdfIn PDF document text
    • https://caror.hu/ckfinder/userfiles/files/mavudunuvapanuv.pdfIn PDF document text
    • http://babamoleskine.com/files/file/pagavofonobijabo.pdfIn PDF document text
    • https://hoakhanh.vn/uploads/image/files/joxuworesakumitumiz.pdfIn PDF document text
    • https://emauto.lv/index/images/up/file/9922979907.pdfIn PDF document text
    • http://www.medicalalliedtraining.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a7604a30579---zusezekudelevefadudito.pdfIn PDF document text
    • https://autotrilogy.com/wp-content/plugins/super-forms/uploads/php/files/caf3b204ab2026429a951b5f70e5461a/jumab.pdfIn PDF document text
    • http://vipnovini.bg/root/f/uploads/files/kufuligifon.pdfIn PDF document text
    • http://brothersaluminium.com.np/wp-content/plugins/formcraft/file-upload/server/content/files/1608766ac54e96---tojisokumugeritifivu.pdfIn PDF document text
    • http://sh8ke.com/wp-content/plugins/formcraft/file-upload/server/content/files/16080baac54c8f---63685476467.pdfIn PDF document text
    • https://plentis.eu/ckfinder/userfiles/files/83563722376.pdfIn PDF document text
    • https://proff-doors.ru/wp-content/plugins/super-forms/uploads/php/files/a739e13f55b142f71b2ac34af234a149/vanerukuj.pdfIn PDF document text
    • https://joefairless.com/wp-content/plugins/super-forms/uploads/php/files/279615659a736d4eacb60f792c676f3c/siluloxexowabisotiguv.pdfIn PDF document text
    • https://deconkhoemanh.com/wp-content/plugins/super-forms/uploads/php/files/p30h1a09er6mlt04m1b42rvq1l/89947338509.pdfIn PDF document text
    • https://www.almuhja.com/ckfinder/userfiles/files/39695688739.pdfIn PDF document text
    • http://allg-gyn.ch/userfiles/file/kiwagedazero.pdfIn PDF document text
    • http://animationcoach.com/userfiles/file/39655976112.pdfIn PDF document text
    • http://hollywoodterrace.org/clients/863344/File/35272771360.pdfIn PDF document text
    • https://divanich96.ru/admin/ckfinder/userfiles/files/jirosutirajat.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_off0000d4c9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD4C9 11496 bytes
SHA-256: 6bed6b91452bbebda7ef961f5044be8619437d1aaffbd3a8fa8147d9f8fd0671
font_01_sfnt_off0000ef6c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEF6C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001077e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1077E 18548 bytes
SHA-256: c9fe0d764fd4089fffdaf72906d68ae117a4287bb625ffb7eeb9e4e4ddd9163f