Malicious PDF — malware analysis report

Static analysis result for SHA-256 331cfa7d159d0eed…

MALICIOUS

PDF

78.6 KB Created: 2021-09-30 10:12:26 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-31
MD5: caa6bc9d2672c33e0f7c8e230bac604b SHA-1: 0b637f654005e54431516b9485c1765e4214e166 SHA-256: 331cfa7d159d0eed921f9e18b1e646ec23d534f60722b1d24b2a1eed51476b49
156 Risk Score

Malware Insights

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

The PDF file was flagged by multiple heuristics, including a critical ClamAV detection and an ML classifier, indicating malicious intent. The presence of a link farm on disposable hosting, with numerous links pointing to PDF files, suggests a phishing or malware distribution attempt. The document body is heavily obfuscated and contains no readable text, further supporting the malicious nature.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9780

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 http://kossuthdigisuli.hu/userfiles/file/jotujodupibarov.pdf In PDF document text
    • http://gardens-spa.com/user_pict/file/1783444688.pdfIn PDF document text
    • https://cremeconferences.com/wp-content/plugins/super-forms/uploads/php/files/955aba2eaabc012a8caa67a474a6b443/1494760414.pdfIn PDF document text
    • https://landtop.com/filespath/files/20210910125333.pdfIn PDF document text
    • https://ljlconst.com/admin/images/file/61015990692.pdfIn PDF document text
    • http://flightshop.jp/images/blog/file/65207479223.pdfIn PDF document text
    • http://businessplan-capalpha.fr/mbp/upload/images/images/upload/ckfinder/73021770994.pdfIn PDF document text
    • https://ratsimae.ee/media/contents/file/damunaw.pdfIn PDF document text
    • http://globalsublimation.net/uploadfile/files/19267467395.pdfIn PDF document text
    • http://droneducational.com/admin/userfiles/file/joveriferi.pdfIn PDF document text
    • http://abwingsbuffalo.com/uploads/files/65444841634.pdfIn PDF document text
    • http://paraglider24.de/pics/fotos/1/file/tizovuduradid.pdfIn PDF document text
    • http://erimti.com/userfiles/file/lanasimotezibop.pdfIn PDF document text
    • http://ikkosushi.com/uploads/files/ladikove.pdfIn PDF document text
    • http://pagyesa.org/userfiles/file/20210911174706.pdfIn PDF document text
    • http://ntep2008.com/UserFiles/File/xatuzab.pdfIn PDF document text
    • https://europawindow.com/app/webroot/img/main_content/files/98133872322.pdfIn PDF document text
    • http://nceed.kr/pds/userfiles/files/66102172591.pdfIn PDF document text
    • http://metallpress.ru/files/fejexaj.pdfIn PDF document text
    • https://study-go.info/wp-content/plugins/super-forms/uploads/php/files/2c970dc1a8a6250d8aa42b29d4df131d/30486900086.pdfIn PDF document text
    • http://puzynowska-kancelaria.com/userfiles/file/jekad.pdfIn PDF document text
    • https://www.digitalsofts.com/wp-content/plugins/formcraft/file-upload/server/content/files/16153e7286e00c---someti.pdfIn PDF document text
    • http://ig-einheitsloks.de/medien/file/fakunimewuwagikeramima.pdfIn PDF document text
    • http://vncdata.net/app/webroot/uploads/files/levukari.pdfIn PDF document text
    • http://veiligheidssloten.nl/ckfinder/userfiles/files/mafupujukoduva.pdfIn PDF document text
    • https://too.kg/wp-content/plugins/super-forms/uploads/php/files/71e84cee233fdb98ae774223eed7910d/vavuwipin.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/ngfLrbzwjls/uplcv?utm_term=download+gloud+games+offline+apkPDF 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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_005_off0000e717.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0xE717 18140 bytes
SHA-256: 3b22649405bd7033eb78591bba0b248fc2a445789774df2b8abd9b9e98a094fa
font_00_sfnt_off0000b5e5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB5E5 10924 bytes
SHA-256: 75a8720c9ae2e7c14c64783c546d390d3d5da72b5732957dce82d2500112c01a
font_01_sfnt_off0000cf06.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCF06 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_03_sfnt_off00010343.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10343 15792 bytes
SHA-256: 052036969d24611f6d79b3f425ed4da46d2dba38f60823a77d41147a03ddf6f5