Malicious PDF — malware analysis report

Static analysis result for SHA-256 51aec226e2a7aef6…

MALICIOUS

PDF

83.8 KB Created: 2021-08-20 17:57:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-16
MD5: 8b0d510e8a4f2b04979cac1152bb4cfd SHA-1: b7decd8c8f41b760145b8c99feed1fea541488dc SHA-256: 51aec226e2a7aef6e5816af8a8ac02134d3d3efebf891b367981fd86684b4436
164 Risk Score

Malware Insights

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

The sample is a PDF containing embedded JavaScript and multiple external URIs. Heuristics indicate it functions as a link farm, pointing to compromised WordPress upload directories. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or distributing further malware. The embedded JavaScript may be used to facilitate the redirection or exploit vulnerabilities.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

Heuristics 7

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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.hptindia.com/wp-content/plugins/formcraft/file-upload/server/content/files/16086fdd521e03---50361437805.pdf In PDF document text
    • http://edumedcare.pl/upload/files/72366640100.pdfIn PDF document text
    • http://kanchanaspa.com/ckfinder/userfiles/files/vupukawamopukegujisu.pdfIn PDF document text
    • http://www.ppk-kp3k.kkp.go.id/ver2/extra/ckfinder/core/connector/php/media/ckfinder/files/lepudegudifazagumo.pdfIn PDF document text
    • http://www.kzhep.in.ua/wp-content/plugins/super-forms/uploads/php/files/a1nh9tusbv5agjtco9freo5137/625674354.pdfIn PDF document text
    • https://quickonboarding.com/wp-content/plugins/super-forms/uploads/php/files/a0c1720294155bcca792d2308ec58c4f/rufusinulovoduv.pdfIn PDF document text
    • http://tageedesign.com/ssmpt/documents/file/34285444141.pdfIn PDF document text
    • http://www.expertnutritionadvisor.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608c351004855---gupajokizufajisol.pdfIn PDF document text
    • https://polresseluma.com/assets/ckfinder/core/connector/php/uploads/files/kiziki.pdfIn PDF document text
    • https://nationalcardsolutions.com/wp-content/plugins/formcraft/file-upload/server/content/files/160dce85905717---49301289428.pdfIn PDF document text
    • https://atlastoursntravels.com/userfiles/file/xejunenonidadapef.pdfIn PDF document text
    • http://amtutoring.com/clients/865321/File/89825115584.pdfIn PDF document text
    • https://its-bulgaria.bg/files/file/66152281563.pdfIn PDF document text
    • http://komputerzagrosze.pl/userfiles/file/pijenawiwowekixa.pdfIn PDF document text
    • http://bagpack.com.np/wp-content/plugins/formcraft/file-upload/server/content/files/160b90e49333d6---tekawex.pdfIn PDF document text
    • http://bet-balance.com/userfiles/file/95839412042.pdfIn PDF document text
    • http://elm3rad.comfile/datatojixomorakirogifosob.pdfIn PDF document text
    • http://garage-ys.info/js/upload/files/pexasutajobarenebez.pdfIn PDF document text
    • https://www.ewdel.cz/ckfinder/userfiles/files/livunamexobewamivedite.pdfIn PDF document text
    • http://bjhtdszdh.com/v15/Upload/file/20215202316234461.pdfIn PDF document text
    • https://bbensonmft.com/wp-content/plugins/super-forms/uploads/php/files/ba0cdbd2c64adc7e190160c582cfeb4e/42249705888.pdfIn PDF document text
    • https://amalighting.com/wp-content/plugins/super-forms/uploads/php/files/7318a4db382b3e6f6d44bc88b69d7ff4/fatubegox.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/1xuhb7AK25c/uplcv?utm_term=araba+sevdas%C4%B1+roman%C4%B1+karakterleriPDF 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_off0000e10e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE10E 18924 bytes
SHA-256: bf57db935cc984421883d35911c70f6262eb9566f4dfc44f3d56c19f72634eb4
font_01_sfnt_off00010ed9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10ED9 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000126f0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x126F0 10736 bytes
SHA-256: d520f75711ab4a34fb237c8ec67a693fa91e49abda8aaca75ed5e7dfe856c5bf

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