Malicious PDF — malware analysis report

Static analysis result for SHA-256 f23ce553dda2d957…

MALICIOUS

PDF

76.2 KB Created: 2021-09-12 21:03:58 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 00f55848fd120de556b5068de1a7e290 SHA-1: d58012b6d23e1cd3106105ec87686eb0da19d384 SHA-256: f23ce553dda2d9572aaee7f9f1445f87ee47569514e8d66482904e9b2ab3394e
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file is a PDF containing embedded JavaScript, which is a common technique for malicious PDFs. Heuristics indicate it functions as a link farm, directing users to multiple external websites, some of which are hosted on compromised CMS platforms or disposable domains. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9948

Heuristics 7

  • 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.
  • 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://medvor.ru/uplcv?utm_term=theoretical+and+experimental+probability+worksheet+with+answers+pdf PDF link annotation
    • http://cybernet-ap.com/UserFiles/File/40627936397.pdfIn PDF document text
    • http://www.ecostroyservis.ru/File/16449110189.pdfIn PDF document text
    • http://www.gyndoktors.de/ckfinder/userfiles/files/4460865274.pdfIn PDF document text
    • http://boschvietnam.com/files/usersfiles/files/xikoviz.pdfIn PDF document text
    • http://vet-spb.com/userfiles/file/11072201101.pdfIn PDF document text
    • http://hidrometa.com/images_upload/files/kugulafiwalujudalotagumu.pdfIn PDF document text
    • http://antik-cafe-bergen.de/wp-content/plugins/formcraft/file-upload/server/content/files/1612ecafe4502f---fatokutewaxutapozirar.pdfIn PDF document text
    • http://tuecpa.com/file_media/file_image/file/85468045315.pdfIn PDF document text
    • http://fazendasaojudastadeu.net/fotosempresa/files/putigakofa.pdfIn PDF document text
    • http://rioairporttransfer.com/ckfinder/userfiles/files/76389165666.pdfIn PDF document text
    • https://www.dynasil.com/wp-content/plugins/super-forms/uploads/php/files/394efa45b2aaaa5068bcb07f3e58e819/51644485441.pdfIn PDF document text
    • https://www.lavishlook.se/wp-content/plugins/super-forms/uploads/php/files/daa7ed82760430889b2a12f18c70e2fe/43941509059.pdfIn PDF document text
    • https://neksav.com/upload/ckfinder/files/91808314024.pdfIn PDF document text
    • http://usefchina.com/uploadfile/file///2021091119170177.pdfIn PDF document text
    • http://caogenzhiben.com/filespath/files/20210909091333.pdfIn PDF document text
    • http://logicparcel.net/uploadsEditorfile/76458011024.pdfIn PDF document text
    • http://holland-ex.com/images/blog/file/8419400533.pdfIn PDF document text
    • https://szpital-sulecin.pl/images/fckfiles/file/dofuvakeb.pdfIn PDF document text
    • http://ilovestory.com/upload/file/62876749596.pdfIn PDF document text
    • https://linlinline.biz/js/ckfinder/userfiles/files/raxawanagopokixu.pdfIn PDF document text
    • http://olech-rzeszow.pl/userfiles/file/mevozos.pdfIn PDF document text
    • http://nemochem.cn/upload/files/49288538461.pdfIn PDF document text
    • http://tavio.su/files/file/82020019705.pdfIn PDF document text
    • https://projektovanje.info/userfiles/file/mexinafi.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_off0000c0bf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC0BF 11380 bytes
SHA-256: c7b8d9dbb7a0e46eb2596a3fbaa74a02f6312ba4d11e7caf40e8c5d47c4b8817
font_01_sfnt_off0000db39.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDB39 18068 bytes
SHA-256: 66c413de1a9ab036698b2131d4738aea88d488e935ccbb1c63ae1cc99036ef65
font_02_sfnt_off00010a50.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10A50 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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