Malicious PDF — malware analysis report

Static analysis result for SHA-256 a157fcfb373268dc…

MALICIOUS

PDF

71.5 KB Created: 2021-09-06 00:06:06 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: 393da4e3d0728338be1a83553526bfca SHA-1: b02e6599168d476fa9753b66bfd1e66556297ec3 SHA-256: a157fcfb373268dcfef0ef1327a394ebe4db629deaed16fc2379fd50b88d2be3
156 Risk Score

Malware Insights

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

The PDF contains a link farm directing to numerous external URLs, with several hosted on compromised WordPress upload directories. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. The structure suggests an attempt to leverage SEO or compromised sites to lure victims.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

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://invest.pl/userfiles/file/33532107972.pdf In PDF document text
    • https://borderpak.com/wp-content/plugins/super-forms/uploads/php/files/c057d1d5fbbc728044ff948b901c481b/40814512556.pdfIn PDF document text
    • https://fizjolech.pl/userfiles/file/noxozulamukima.pdfIn PDF document text
    • https://fotojursa.cz/userfiles/file/fuvupefidosikuvife.pdfIn PDF document text
    • https://castel.ro/userfiles/file/16421371174.pdfIn PDF document text
    • http://ozona.pt/wysiwygfiles/file/79243485087.pdfIn PDF document text
    • https://bustotoronto.com/userfiles/file/26445415304.pdfIn PDF document text
    • http://www.johnknox.ch/wp-content/plugins/formcraft/file-upload/server/content/files/160b40442d18b2---dikamudutokuli.pdfIn PDF document text
    • http://omonetach.pl/foto/ilustracje/file/wibosedo.pdfIn PDF document text
    • http://iideree.org/wp-content/plugins/formcraft/file-upload/server/content/files/160e6b3428bfa9---18749053779.pdfIn PDF document text
    • http://www.sunargrup.com.tr/wp-content/plugins/super-forms/uploads/php/files/mrmmob7c239k2vktbhjlga83n0/denubiguson.pdfIn PDF document text
    • http://cuatudongbinhduong.net/uploads/files/bejizilelifopo.pdfIn PDF document text
    • http://lignumweb.com/site/webroot/uploads/files/69336533792.pdfIn PDF document text
    • http://leinerpakgelatine.com/survey/userfiles/files/78777178329.pdfIn PDF document text
    • http://www.etoiles-recrutement.com/wp-content/plugins/formcraft/file-upload/server/content/files/16135308c4afdc---domixek.pdfIn PDF document text
    • http://levakov132.ru/userfiles/file/36883124526.pdfIn PDF document text
    • https://shindah.com/images/ckeditor_img/files/remeguzilisowix.pdfIn PDF document text
    • https://unitedcardsolutions.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b8bad0a917a---binekijunewaxepeg.pdfIn PDF document text
    • http://briztravel.com/upload/files/rulabapidibezemowi.pdfIn PDF document text
    • https://optical-axis.com/uploads/files/202108250229103877.pdfIn PDF document text
    • https://hmanagement.net/userfiles/file/lovorogesewafenorival.pdfIn PDF document text
    • http://sun-tes.ru/files/file/medusigalivudejaleno.pdfIn PDF document text
    • https://expungemyrecordnj.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607e155e6aea6---taxuxedogutogibamuvux.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/3vuEKuznOb8/uplcv?utm_term=solve+systems+of+equations+by+graphing+worksheet+pdfPDF 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_off0000b3bb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB3BB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000cbd2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCBD2 11764 bytes
SHA-256: 25febdaada583a05e0951fb3665a4345df48b1d0252ee70298266efdfff51ac0
font_02_sfnt_off0000e70f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE70F 16144 bytes
SHA-256: d684fe2eba90bca713e4c740734c0ea8a0fea9e3930884e5fd728c290acabaff

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