Malicious PDF — malware analysis report

Static analysis result for SHA-256 f53994233cf2849a…

MALICIOUS

PDF

72.2 KB Created: 2021-09-16 05:35:08 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 959fbce9d7020c163c2e3162931997a0 SHA-1: bd42cdc07d3d7d4a3beb380ecb1cd1037cba70e4 SHA-256: f53994233cf2849a9a879420b837523f7a2ef90daf8cc0f436d0caee81f542d4
156 Risk Score

Malware Insights

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

The PDF file contains a link farm hosted on a compromised WordPress site, as indicated by the 'PDF_SEO_DISPOSABLE_LINK_FARM' and 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' heuristics. The ML classifier and ClamAV detection strongly suggest malicious intent. The embedded URLs likely serve as redirects to phishing or malware distribution sites, aligning with a spearphishing attachment attack pattern.

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 http://www.unidacardoso.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16132d8f95cdbd---12778376362.pdf In PDF document text
    • http://tidomusica.com/uploads/files/202109140617167290.pdfIn PDF document text
    • https://mymovingestimate.com/wp-content/plugins/super-forms/uploads/php/files/08fef351fa9ea0cee31ff6e6caff2653/6870204237.pdfIn PDF document text
    • https://stcatherine.ac.ug/wp-content/plugins/formcraft/file-upload/server/content/files/1613a9e4d0f184---77566894470.pdfIn PDF document text
    • http://evrokomplekt.ru/userfiles/file/zurutojumobaf.pdfIn PDF document text
    • https://astoraccessories.com/uploads/ckfinder/files/87078124571.pdfIn PDF document text
    • https://ausztriasi.spawellness.hu/upload/hirlevel/files/69442830665.pdfIn PDF document text
    • https://mp2020.csysadmin.com/ckfinder/userfiles/files/repesilefo.pdfIn PDF document text
    • https://www.onestopnaturalstore.ca/wp-content/plugins/super-forms/uploads/php/files/0gtj9poa928ao3ikm0hj99edpo/sejoladutizagilejof.pdfIn PDF document text
    • http://www.huntsvillepr.com/files/files/63739909113.pdfIn PDF document text
    • https://dlt-nkp.com/fileupload/file/jotovasele.pdfIn PDF document text
    • http://tofuyatogo.com/uploads/files/wivesuti.pdfIn PDF document text
    • http://jingmingtai.com/filespath/files/20210909061326.pdfIn PDF document text
    • http://sushiosushi.com/uploads/files/33541855032.pdfIn PDF document text
    • https://sunnyvale.com/wysiwygfiles/file/81069005513.pdfIn PDF document text
    • https://www.wroclawmodelshow.pl/ckfinder/userfiles/files/lebefejuzeximos.pdfIn PDF document text
    • http://hengfengpaper.com/filespath/files/20210913080300.pdfIn PDF document text
    • http://wasserentkalkung.at/ckfinder/userfiles/files/nukovajemebuxevanesi.pdfIn PDF document text
    • http://yugang360.com/upload_fck/file/2021-9-10/20210910070529565242.pdfIn PDF document text
    • http://www.ctnphrae.com/ckfinder/userfiles/files/48802557508.pdfIn PDF document text
    • http://stnicholasway.com/userfiles/file/fesusebubugutezab.pdfIn PDF document text
    • http://e-instar.com/userfiles/file/xotetonidapuxomalavufawo.pdfIn PDF document text
    • https://orrizon.ru/images/file/rupon.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/cv9VXjIrmdE/uplcv?utm_term=adult+stem+cells+pros+and+consPDF 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_off0000b821.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB821 10664 bytes
SHA-256: e5dc86bfe1b3573efd55848eb88e30a97241d6d2ca1d691c9e53d1bec47043a7
font_01_sfnt_off0000d093.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD093 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000e8a5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE8A5 16656 bytes
SHA-256: 74e3e8eaf0be8255a63c7bdab1b749a80ccc11faaa3f723aae681af86fbc435b

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