Malicious PDF — malware analysis report

Static analysis result for SHA-256 9c31a7ddf4097e26…

MALICIOUS

PDF

81.1 KB Created: 2021-09-10 21:50:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 4647316bbf036d80a6ee33138167dbde SHA-1: 13efebbc4acdfd7e16d7f44c607e308245896278 SHA-256: 9c31a7ddf4097e26f9b2ee88eafcfb32a81a8b4032aac5c9445ce14995810c30
134 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file flagged by ML classifiers and ClamAV as malicious. It contains embedded JavaScript and numerous external URIs, many of which point to PDF files hosted on potentially disposable domains. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic indicates a large number of links to distinct hosts, suggesting a link farm used for SEO poisoning or distributing further malicious content. The embedded JavaScript likely facilitates the redirection or download of additional payloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9949

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
  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://recapress.com/ckfinder/userfiles/files/diberekobatepixuzal.pdf In PDF document text
    • http://aedjtjdshbf.pretty-match.com/upload/files/sopigegovipizatusoluda.pdfIn PDF document text
    • http://www.jacenter.org/js/ckfinder/userfiles/files/93421346433.pdfIn PDF document text
    • https://www.diktu.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613223cd14961---kuzagafutojipat.pdfIn PDF document text
    • http://ingenermarket.ru/userfiles/52054718597.pdfIn PDF document text
    • http://phutungotodungha.com/img/files/lebojutizukuz.pdfIn PDF document text
    • http://biosystech.com/pdsFck/file/muzutubunopakixoput.pdfIn PDF document text
    • https://heatingboiler.ca/fck_upload/file/60137150588.pdfIn PDF document text
    • http://aexpress.lv/index/images/up/file/26724367612.pdfIn PDF document text
    • http://hennel.hu/sources/elemek/file/lovirenuza.pdfIn PDF document text
    • http://flixgolf.com/ckeditor/ckfinder/userfiles/files/nefipitifoxetogujoxi.pdfIn PDF document text
    • https://makanbanyak.net/contents/files/74613745069.pdfIn PDF document text
    • https://tonerihned.cz/userfiles/file/pozoxazekonaraguku.pdfIn PDF document text
    • http://mxm-hosting.nl/img/editor/file/28226321517.pdfIn PDF document text
    • http://chafewyuok.handysociality.com/upload/files/zapazanodugutotinafokuxuz.pdfIn PDF document text
    • http://z-sinpro.com/upload/files/fizepofumerimasujagudovid.pdfIn PDF document text
    • http://www.ktgroup.co.uk/ckfinder/userfiles/files/92336142270.pdfIn PDF document text
    • http://iact2001.com/userData/board/file/43080620239.pdfIn PDF document text
    • https://mmeasar.com/mmeasarfiles/file/94688271870.pdfIn PDF document text
    • https://wamsconference.com/wp-content/plugins/super-forms/uploads/php/files/e31883722c8ac19d4ba9416cb9e22388/16146923217.pdfIn PDF document text
    • https://10playsolutions.com/clients/softklk/documents/_articles_/file/52989186797.pdfIn PDF document text
    • http://archi-m.ru/userfiles/file/44585041838.pdfIn PDF document text
    • http://uralcomservis.ru/crn_fls/crn_files/wabonabupexod.pdfIn PDF document text
    • https://angelsolutions.ro/ckeditor/ckfinder/userfiles/files/80215705074.pdfIn PDF document text
    • http://lyzebrno.cz/userfiles/file/maresofut.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/zMnd8XtcwSM/uplcv?utm_term=how+to+activate+your+sd+cardPDF 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_off0000d948.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD948 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f15a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF15A 17628 bytes
SHA-256: ee9e5ca4854cc94504e84bd045435200db74796a69c20bf02914bcc1caf81918
font_02_sfnt_off00011ee9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11EE9 10572 bytes
SHA-256: 1447d81744a2d2df0052ea2821459693fe059ad6bf3255060bd7e3577b8111b2