Malicious PDF — malware analysis report

Static analysis result for SHA-256 a4b4839a0043f1dc…

MALICIOUS

PDF

91.2 KB Created: 2021-08-11 03:02:33 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-18
MD5: 646f67410f6c6eda0697dc74d7f74277 SHA-1: 3a0f2c384ff3489d4d05b724e8ef0ea8a7b4518f SHA-256: a4b4839a0043f1dc53a1691e43b2c80004a3a12fadec20e557b42340937313ee
156 Risk Score

Malware Insights

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

The PDF contains numerous links to compromised WordPress upload directories, indicating a link farm designed to host and distribute malicious content. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or malware delivery. The document body is unreadable, but the heuristic firings point to a pattern of hosting malicious files on compromised web servers.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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://www.sarajevo-inn-grunewald.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609da9e3cb15f---8626283065.pdf In PDF document text
    • https://www.hotel-palladium.gr/wp-content/plugins/super-forms/uploads/php/files/khktburugdjnsihhiasuj776lr/84030071089.pdfIn PDF document text
    • http://www.niziointerior.pl/upload/file/74454373253.pdfIn PDF document text
    • http://xn--80ackbssfuieecff0e8c.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/5o5k9c3o3bvunk3goec0ccrri6/lisejevozala.pdfIn PDF document text
    • http://www.sempresaude.net/wp-content/plugins/formcraft/file-upload/server/content/files/16085807b18336---46591657333.pdfIn PDF document text
    • https://banghenails.com/upload/file/feguf.pdfIn PDF document text
    • http://fongyoskert.hu/userfiles/files/vusegojilibux.pdfIn PDF document text
    • http://janjoling.com/public/ckfinder/userfiles/files/kubivizetonegopudovatina.pdfIn PDF document text
    • https://infoenergie-loire.org/userfiles/file/5614103499.pdfIn PDF document text
    • http://srividyaastrology.com/userfiles/file/10185446227.pdfIn PDF document text
    • https://ecodiagnost.com/ckfinder/userfiles/files/zaxufapimum.pdfIn PDF document text
    • http://ducthoaudio.com/upload/files/misibadi.pdfIn PDF document text
    • http://amexeuro.com/an3_Uploads/file/59650223621.pdfIn PDF document text
    • https://doctorchina168.com/upload/files/jaxekujifezefatuximuba.pdfIn PDF document text
    • http://cedresarquitectura.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d64c2e59ecf---niguganozadotewoja.pdfIn PDF document text
    • https://www.thaiahpa.com/flash/files/30635235127.pdfIn PDF document text
    • http://moscow-vernisage.com/files/files/lebofibukasodibitajexor.pdfIn PDF document text
    • https://skazkavdom.com/wp-content/plugins/super-forms/uploads/php/files/7fc5b6811d7ce22f3e15d88568864c7c/45277034109.pdfIn PDF document text
    • https://sidexsideaudio.com/wp-content/plugins/formcraft/file-upload/server/content/files/16110e16999201---bodesepej.pdfIn PDF document text
    • http://claudiodauelsberg.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1610c2307a73ae---pozetigodipexok.pdfIn PDF document text
    • https://atrax.hr/files/74501795300.pdfIn PDF document text
    • http://gibisch.biz/files/files/80626053572.pdfIn PDF document text
    • http://nc-israel.ru/upload/files/xitamazubugusebekukarig.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/GLLx1DTH0VQ/uplcv?utm_term=fotos+de+los+10+mandamientos+para+ni%C3%B1osPDF 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_off0000fe26.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFE26 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0001163d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1163D 10912 bytes
SHA-256: 7a75714a2d50120729b5d8789dbd678a2d7f78733b255a989a4bf13273ed0296
font_02_sfnt_off00012f36.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12F36 18648 bytes
SHA-256: a5cfd5b8919fa9a0c75bfc1875d912a74a35772fcad2d21d23f907f286b1fb77