Malicious PDF — malware analysis report

Static analysis result for SHA-256 a851aea18b0a378b…

MALICIOUS

PDF

71.1 KB Created: 2021-10-03 13:16:55 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-02
MD5: 1990c05db82f88aca4d1890526c0368c SHA-1: 7e0ae77a947ec81d69d3c7748f69eda14b03a152 SHA-256: a851aea18b0a378ba8ba980832011be2be68a883abf0eb5736ad1c3283bb3530
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs, many of which point to compromised WordPress sites or disposable hosting, indicating a link farm designed for malicious redirection. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or malware delivery. Although no scripts were explicitly extracted, the structure and URL patterns are consistent with a malicious PDF dropper.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9978

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 https://lee-trading.tw/archive/upload/files/fesuberenubozipodiduvem.pdf In PDF document text
    • http://marymo.ru/uploads/files/3593639090.pdfIn PDF document text
    • http://natpuedu.in/userfiles/file/53543256419.pdfIn PDF document text
    • http://nguoigiupviec99.com/webroot/img/files/xagifajegelurivaze.pdfIn PDF document text
    • https://agronlogistics.com/userfiles/files/tolowo.pdfIn PDF document text
    • http://apluskleaning.com/admin/images/file/97784340889.pdfIn PDF document text
    • https://daqing-jewelry.com/uploads/files/202109220325272803.pdfIn PDF document text
    • http://karaokejdi.com/ckfinder/core/connector/php/upload/files/pugulodejinoluwerebobiti.pdfIn PDF document text
    • http://uleshuzatshop.hu/files/file/bedubufalapalazuralej.pdfIn PDF document text
    • https://bruceautoservice.com/files/file/nanuxotefisorovepipokik.pdfIn PDF document text
    • http://chi-kara.net/Upload/files/wigixojoxuzovopolakiloka.pdfIn PDF document text
    • http://premiumresourcing.com/wp-content/plugins/formcraft/file-upload/server/content/files/1615403181194c---najotawogajadiroxutemodi.pdfIn PDF document text
    • https://myparrotfood.com/user_files/files/31097083568.pdfIn PDF document text
    • http://jingmingtai.com/filespath/files/20210914014427.pdfIn PDF document text
    • http://benthanhsgfarm.com/images/uploads/files/66340022135.pdfIn PDF document text
    • https://notofthisgalaxy.com/wp-content/plugins/super-forms/uploads/php/files/ch3b6i17m0b0iqc2lqrm5d50ni/niwusoniwelul.pdfIn PDF document text
    • http://derkwoo.com/upload/editor/files/81696739335.pdfIn PDF document text
    • https://mdteam.se/ckfinder/userfiles/files/mogunu.pdfIn PDF document text
    • http://www.de.ruben.pl/ckfinder/userfiles/files/29145738288.pdfIn PDF document text
    • http://villa-carlshorst.de/sites/default/files/file/46929827292.pdfIn PDF document text
    • https://ocvirapuato.com.mx/wp-content/plugins/super-forms/uploads/php/files/e9eb3a4b98542bad4de7c9141fd57033/kinewuka.pdfIn PDF document text
    • https://topclassgreenery.nl/images/file/62941694025.pdfIn PDF document text
    • http://www.520amis.com/upload/files/11022900033.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/cv9VXjIrmdE/uplcv?utm_term=5+square+yardsPDF 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_off0000b34f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB34F 17912 bytes
SHA-256: 53b3d0f7de9d88fcdde931e40548bf0dfc09792e5d7262ea6c14f00f14b892e3
font_01_sfnt_off0000e038.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE038 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f84f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF84F 10176 bytes
SHA-256: 9d1676c459653ea7ccd6f03501dcaee9647f9a5bb7d90e28798a1fb2a78b78dd