Malicious PDF — malware analysis report

Static analysis result for SHA-256 4a4277a2b251d13d…

MALICIOUS

PDF

78.0 KB Created: 2021-09-01 14:30:59 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 85ed9afe829353e3457db23e89d8749e SHA-1: ac8f365e60efd5d1d9d355d6edbcbcb0292813ed SHA-256: 4a4277a2b251d13d940daf3b4852f91686b1a19eed082a6ea310a6d5b8fc850d
156 Risk Score

Malware Insights

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

The PDF was identified as malicious by ClamAV and an ML classifier, indicating a phishing or malware distribution intent. It functions as a link farm, with numerous embedded URLs pointing to external sites, several of which are hosted on compromised WordPress installations. The document body is heavily obfuscated and appears to be non-readable content generated by wkhtmltopdf, providing no direct user-facing lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9934

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://queure.ru/uplcv?utm_term=what+is+a+normal+good+in+economics PDF link annotation
    • https://canvasations.com/wp-content/plugins/super-forms/uploads/php/files/5b8mmt558sokk4l8mm3lq2f4r6/mumolomuzofoxoki.pdfIn PDF document text
    • https://bmw-zona.ru/uploads/file/nusejipuxemibazixed.pdfIn PDF document text
    • https://action-roofing.com/wp-content/plugins/super-forms/uploads/php/files/b4ca635d499f5428fd39e7c8fa9af9f9/vokos.pdfIn PDF document text
    • http://thoitrangvabaoho.com/Images_upload/files/giragorudi.pdfIn PDF document text
    • https://daleel.global/wp-content/plugins/super-forms/uploads/php/files/vnh7frs1a4ma094gbr1bfads8p/tixasibekupagom.pdfIn PDF document text
    • http://dh-cell.com/ckfinder/userfiles/files/29959387695.pdfIn PDF document text
    • https://earthchartercities.org/wp-content/plugins/formcraft/file-upload/server/content/files/16086c79b0d256---22319542901.pdfIn PDF document text
    • https://bookatowncar.com/userfiles/file/jedutagutofegafodojim.pdfIn PDF document text
    • http://novichiha.ru/pic/file/45326423520.pdfIn PDF document text
    • https://grand-forge.ru/wp-content/plugins/super-forms/uploads/php/files/668429995b2d1be86ffc90e2b0fa98d1/8331847977.pdfIn PDF document text
    • https://sharjahcements.com/images/bulk_images/files/posubedef.pdfIn PDF document text
    • http://fixafilm.se/userfiles/file/bitonugijimazajupapodudim.pdfIn PDF document text
    • http://leadingedgecorporate.com/user_images/file/81862357929.pdfIn PDF document text
    • https://alcc.vn/wp-content/plugins/super-forms/uploads/php/files/qjak2bj289692qkrl6tbuusta0/81064914887.pdfIn PDF document text
    • http://fpole.ru/sadm_files/basujikozipuwan.pdfIn PDF document text
    • https://nhahangphongcanh.com/uploads/files/26004363076.pdfIn PDF document text
    • https://clickkedai.com/userfiles/file/velorevuputagif.pdfIn PDF document text
    • http://www.mearesandassociatesllc.com/siteuploads/editorimg/file/80753117696.pdfIn PDF document text
    • http://aiswaryamatrimonials.com/fck_uploads/file/69090489428.pdfIn PDF document text
    • http://makaifruits.com/wp-content/plugins/formcraft/file-upload/server/content/files/16077bf846cb0e---wewela.pdfIn PDF document text
    • https://qboardapp.com/wp-content/plugins/super-forms/uploads/php/files/ff59bb2eb1231c56cde15d5cdcb61276/22104166887.pdfIn PDF document text
    • http://pogservice.ru/userfiles/file/mokotara.pdfIn PDF document text
    • http://xn--k1akb4c.xn--p1ai/userfiles/file/75874140981.pdfIn PDF document text
    • https://simondaulte.com/ckfinder/userfiles/files/56328157311.pdfIn PDF document text
    • http://gernano.eu/gfx/userfiles/files/12049998050.pdfIn PDF document text
    • http://omonetach.pl/foto/ilustracje/file/61463068497.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_off0000cbab.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCBAB 17332 bytes
SHA-256: a94f89b84f5b901778b34a44c41551ecf16e35b2b3ba982be133a53405efaac4
font_01_sfnt_off0000f868.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF868 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001107f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1107F 10808 bytes
SHA-256: c8401e0ae440b03ead0c116ba12d89dfdd2946c0eb05435cb6e2466904751d84

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