Malicious PDF — malware analysis report

Static analysis result for SHA-256 8f22c71fc283b7a2…

MALICIOUS

PDF

75.0 KB Created: 2021-09-06 12:56:04 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-31
MD5: bea4cc011f61329f6e50c0273eed95fb SHA-1: d68e2bf8e57fda6e023a2a42d998e218dc43a6f1 SHA-256: 8f22c71fc283b7a28abd15260292d0b1a1f631e8048457e7c8f7dd2be3cfbc82
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains numerous external links, many hosted on what appear to be compromised websites or disposable domains, indicative of a link farm used for phishing or malware distribution. The ML classifier and ClamAV detection strongly suggest malicious intent. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, further supporting the idea that the content is not user-facing but rather a vehicle for malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

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://archism.ru/uplcv?utm_term=biophilic+design+research+paper+pdf PDF link annotation
    • https://gameclub.by/uploads/files/siwalorazabawesedozipogi.pdfIn PDF document text
    • http://blpest.com/UserFiles/file/3562306935.pdfIn PDF document text
    • https://www.intermediastudios.com.mx/wp-content/plugins/super-forms/uploads/php/files/9d6ccd8dae01916169b7734decfe9579/bosena.pdfIn PDF document text
    • http://festivaldeliteraturadepereira.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613421bf06e17---jotoki.pdfIn PDF document text
    • https://pasationtravellers.com/root/FCKeditor/file/nifufitarowofuvugebip.pdfIn PDF document text
    • https://www.americanapi.com/wp-content/plugins/formcraft/file-upload/server/content/files/160abccc18bff6---dawapajizad.pdfIn PDF document text
    • http://szyoujin.com/UploadFile/file/20210904032625323.pdfIn PDF document text
    • http://brandiassociati.it/userfiles/file/bijajilubel.pdfIn PDF document text
    • http://archinfo.ru/uploads/file/95383689917.pdfIn PDF document text
    • http://www.sg-callenberg.de/wp-content/plugins/formcraft/file-upload/server/content/files/16113cd13c4392---xeselidepawimamol.pdfIn PDF document text
    • http://bitite.lv/media/txt/122/file/65488680577.pdfIn PDF document text
    • http://kozszemle.hu/uploads/files/warixovelakuxijamig.pdfIn PDF document text
    • http://ozdesignhouse.com/app/webroot/uploads/files/jedefegedijiminojiretonu.pdfIn PDF document text
    • http://ukicda.com/admin/fckeditor_upfiles/file/2021072423503280554.pdfIn PDF document text
    • https://fizjolech.pl/userfiles/file/22800812427.pdfIn PDF document text
    • https://theshairpodcast.com/wp-content/plugins/super-forms/uploads/php/files/6f17f213c040be15e16075b53033d958/71292496128.pdfIn PDF document text
    • https://www.avenueroadadvertising.com/wp-content/plugins/formcraft/file-upload/server/content/files/160866f885d791---47791253158.pdfIn PDF document text
    • https://drahmetbostanci.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607cf604b3d36---77474728365.pdfIn PDF document text
    • https://www.oneirishrover.com/wp-content/plugins/super-forms/uploads/php/files/bd00c5e90251a591103146ba32eb9af9/volilaziporujiseje.pdfIn PDF document text
    • https://nnt52.ru/userfiles/file/53349685664.pdfIn PDF document text
    • http://theseadiaries.com/ckfinder/userfiles/files/zuwosas.pdfIn PDF document text
    • https://hyosungulf.com/uploads/file/raturu.pdfIn PDF document text
    • 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_off0000c395.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC395 10852 bytes
SHA-256: d5f92b51045bfbefdd1c99a2bddf1294deb0953591b05e24920888354b317808
font_01_sfnt_off0000dc5d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDC5D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f46f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF46F 16316 bytes
SHA-256: a534abba6c823113904508a6035ce3a6125ac0e208df07007fa9a31939993d85

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