Malicious PDF — malware analysis report

Static analysis result for SHA-256 21b79bf5adc41443…

MALICIOUS

PDF

90.9 KB Created: 2021-09-18 09:05:29 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 0af7876fa0726ed8b7c53b7cdee75f63 SHA-1: 2199353cbf01dffeeb537487719c9f2c7a694cd4 SHA-256: 21b79bf5adc41443fe87fb8a4f664b537333966dd5a1705e66cb07bbbe79836f
164 Risk Score

Malware Insights

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

The sample is a PDF file containing embedded JavaScript, which is a common technique for executing malicious code. The presence of numerous external links, including those hosted on compromised CMS uploads and disposable domains, strongly indicates a phishing or malicious redirection campaign. The ML classifier and ClamAV detection further support the malicious nature of this file.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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 https://kudamatsu.org/userfiles/file/zetelemazaxupalesebol.pdf In PDF document text
    • http://juditphotography.com/picture/userfiles/file/42381997599.pdfIn PDF document text
    • http://mitchelllawoffice.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/74893740791.pdfIn PDF document text
    • http://helloslow.com/data/userfiles/files/60802254387.pdfIn PDF document text
    • http://jaqalsports.com/files/file/56494755792.pdfIn PDF document text
    • https://j26clean.com/upload/files/vamazanakivapivaromatab.pdfIn PDF document text
    • https://lisacutler.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613e0d08b4754---25416695134.pdfIn PDF document text
    • http://www.rlktechniek.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1613214f52635e---jasusufazeketaxejofe.pdfIn PDF document text
    • https://asztromiskolc.hu/ckfinder/userfiles/files/kekobomukup.pdfIn PDF document text
    • http://highendschmiede.de/highendfiles/file/60023891356.pdfIn PDF document text
    • http://otoozevran.com/resimler/files/zokug.pdfIn PDF document text
    • http://cjcounsel.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/vajavolitunipelefikon.pdfIn PDF document text
    • http://hoaiduc.edu.vn/ckfinder/userfiles/files/40149438780.pdfIn PDF document text
    • http://njbeihang.com/uploadfile/file///2021090520513036.pdfIn PDF document text
    • https://www.sensormaticltd.com/app/templates/js/ckfinder/userfiles/files/sijutofumabame.pdfIn PDF document text
    • http://kolesnikov.pro/ckfinder/userfiles/files/sujunikepevexilob.pdfIn PDF document text
    • https://sharks-cz.cz/images/file/zerurefu.pdfIn PDF document text
    • http://yogo110.com/userfiles/file/77668222905.pdfIn PDF document text
    • http://nuyewrecruitment.com/wp-content/plugins/super-forms/uploads/php/files/76b776ff6a92fd1c45e3eb3eef3dc816/75169352722.pdfIn PDF document text
    • https://www.ventisilva.com.br/ckfinder/userfiles/files/13558237643.pdfIn PDF document text
    • http://xn--80aer5aza.xn----htbdepbihnfb8cyg.xn--p1ai/ckfinder/userfiles/files/63731923984.pdfIn PDF document text
    • http://mnwebdesign.dk/userfiles/file/davemibarifuwot.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/1xuhb7AK25c/uplcv?utm_term=free+tv+player+windows+7PDF 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_off0000fb71.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFB71 10680 bytes
SHA-256: bf3c3910616793f76af96b1b13ad46412adc570a47cd1d5a3fb348142d46bf65
font_01_sfnt_off00011423.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11423 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012c35.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12C35 19188 bytes
SHA-256: ac739341ea04ffa7c880c75a6f308f969b30056d39eb44e65e0b73aa6322bf3f

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