Malicious PDF — malware analysis report

Static analysis result for SHA-256 5ff85b76ce186f55…

MALICIOUS

PDF

91.7 KB Created: 2021-09-07 16:07:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 70f566f3b8d730635bc2d570a0cc8947 SHA-1: 683645950ce64005346f1c84875eaa2ebfd921e3 SHA-256: 5ff85b76ce186f55202ac3e77d32a65f368d93b192c322ee96ac614edbd21a2d
156 Risk Score

Malware Insights

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

The PDF was flagged by a machine learning classifier and ClamAV as malicious. Static analysis revealed it functions as a link farm, containing numerous URLs pointing to other PDF files hosted on compromised websites. These links likely serve as lures for phishing attacks or to distribute further malware. No scripts were extracted from this sample.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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://ducthoaudio.com/upload/files/supuxekebu.pdf In PDF document text
    • https://smilepath.com.au/wp-content/plugins/super-forms/uploads/php/files/4b1fa8a1170e78057b7ea92235081678/borutututudunuvisege.pdfIn PDF document text
    • http://c2ctrading.org/cms_upload/files/bebikim.pdfIn PDF document text
    • https://www.benkorner.nl/admin/library/ckfinder/userfiles/files/16192908952.pdfIn PDF document text
    • http://asckhn.com/acskhn/userfiles/file/5415944900.pdfIn PDF document text
    • https://grupo-bahia-real-estate.com/ckfinder/userfiles/files/lewekazexupid.pdfIn PDF document text
    • http://studiophotosfashion.it/userfiles/files/rexav.pdfIn PDF document text
    • http://totoquynhhuong.com/upload/files/bubuwe.pdfIn PDF document text
    • http://angelojrobles.com/admin_initial_test/userfiles/file/woziwiwar.pdfIn PDF document text
    • https://pinotcar.com/wp-content/plugins/super-forms/uploads/php/files/2faaf24791177cd4213d698c455e01bf/tojesuzevipasofabugedunum.pdfIn PDF document text
    • http://laclonghotel.vn/upload/files/finikefedi.pdfIn PDF document text
    • http://gostium.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606f0cc9319cd---58474725013.pdfIn PDF document text
    • https://dungcuruamui.com/wp-content/plugins/super-forms/uploads/php/files/ol7lcqoc2p8m7fjthuih8en8ao/figaloxaworob.pdfIn PDF document text
    • http://www.niziointerior.pl/upload/file/vetopadonatubokedigi.pdfIn PDF document text
    • https://egyiksem.hu/uploads/file/76638731132.pdfIn PDF document text
    • http://sjhrz.com/images/upload/File/dugudewatizitulukigi.pdfIn PDF document text
    • https://wentworthre.com/wp-content/plugins/super-forms/uploads/php/files/7c4f7a6d3ba987746178e6c9be6f5590/numuxunetizeserefoguzokow.pdfIn PDF document text
    • https://hasekei.jp/userfiles/file/movawemitumidafinuj.pdfIn PDF document text
    • http://www.yourhealthyourchoice.org/wp-content/plugins/formcraft/file-upload/server/content/files/16072e1133b788---9007429260.pdfIn PDF document text
    • https://digireg.si/upload/36364286734.pdfIn PDF document text
    • http://training-solutions.ro/wp-content/plugins/formcraft/file-upload/server/content/files/16118555d837b5---29605104789.pdfIn PDF document text
    • http://caribsplash.org/wp-content/plugins/formcraft/file-upload/server/content/files/160c34f07e499f---katifi.pdfIn PDF document text
    • https://kakvkusno26.ru/wp-content/plugins/super-forms/uploads/php/files/b394cf979a8e04897405ed2e5bec959a/vaketabaxun.pdfIn PDF document text
    • http://www.lavalledesign.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a835d1b5995---12583802828.pdfIn PDF document text
    • https://www.crossfitparamaribo.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b00e12358b3---xabenegivisotenelinu.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/Om9ozkHLxGw/uplcv?utm_term=download+kitab+kuning+pdf+androidPDF 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_off0000ffaf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFFAF 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off000117c1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x117C1 18552 bytes
SHA-256: 75bd48895e8a79bc08ad0e4a2c397ffbe8c2155ebdf4fd959357f383cca80a96
font_02_sfnt_off00014824.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14824 10792 bytes
SHA-256: 38f925558adba0c43e41325b90e19710bd3ee15beecd59ac8d1d984920427d09