Malicious PDF — malware analysis report

Static analysis result for SHA-256 25509c10790a5611…

MALICIOUS

PDF

88.2 KB Created: 2021-09-18 08:44:24 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: a7a7906323a941c931b8610bd769450f SHA-1: 8386eb1fd6fe428113243612de934aa7f649f9a2 SHA-256: 25509c10790a561140d6ca031ca5d60230d558483e4e632caa044855336c473c
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs that point to various domains, many of which are associated with file hosting or user uploads, suggesting a link farm designed to distribute malicious content. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' strongly indicates this is a tactic to obscure malicious destinations.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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.
  • 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://we-plus.tw/ckfinder/userfiles/files/vubujijaxaxafoxuj.pdf In PDF document text
    • https://eminenceconstruction.ca/viking1/uploads/files/97333958015.pdfIn PDF document text
    • http://wcsps.com.tw/ckfinder/userfiles/files/bosogiwulefejabuj.pdfIn PDF document text
    • https://saikekanglun.com/filespath/files/20210911160201.pdfIn PDF document text
    • http://nemeckystrakac.sk/editor_uploads/files/wituwe.pdfIn PDF document text
    • https://evocative.ru/wp-content/plugins/formcraft/file-upload/server/content/files/161449d1a35cfa---zefefelabuvirolonofosej.pdfIn PDF document text
    • https://bloomlight.pl/_bloom/file/nokepigufugazika.pdfIn PDF document text
    • https://booknowrentalimo.ch/userfiles/files/nefudero.pdfIn PDF document text
    • http://eko-baby.ru/userfiles/file/kiruwixadonuvonemif.pdfIn PDF document text
    • https://colegiumaniucarei.ro/ckfinder/userfiles/files/75970069953.pdfIn PDF document text
    • https://tvsporedi.si/vsebina/gemogolejuw.pdfIn PDF document text
    • http://dichvuhieuchuan.com/upload/files/36979868985.pdfIn PDF document text
    • http://gulfcoastlist.com/userfiles/file/28300822735.pdfIn PDF document text
    • http://fongyoskert.hu/userfiles/files/22259464720.pdfIn PDF document text
    • http://akcompany.vn/uploads/userfiles/file/14714761523.pdfIn PDF document text
    • http://jjkxmy.com/upload/files/202109051648041454.pdfIn PDF document text
    • http://jungam21.com/upfiles/file/1630656201.pdfIn PDF document text
    • http://www.tobywells.org/media/fckdir/file/gefik.pdfIn PDF document text
    • https://butyfarm.mm520.net/userfiles/files/jixusi.pdfIn PDF document text
    • http://zjnep.com/ckeditor/ckfinder/userfiles/files/xudiji.pdfIn PDF document text
    • https://avigailpekelman.com/sites/default/files/file/zazuxekekonubowesexelunez.pdfIn PDF document text
    • http://squarcialupirelaxinchianti.com/writable/public/userfiles/file/53037977029.pdfIn PDF document text
    • https://vonia.mikludava.lt/images/files/dawekukezudarexik.pdfIn PDF document text
    • http://raegcafe.com/uploads/files/63503537938.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/Om9ozkHLxGw/uplcv?utm_term=best+android+app+ideas+for+beginnersPDF 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_off0000f492.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF492 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00010ca4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10CA4 17640 bytes
SHA-256: 54bffa2546b5557d6be240c9d898e8026f004a8f6b751471e22083f6c4d9f325
font_02_sfnt_off00013a8d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13A8D 10820 bytes
SHA-256: 873aed7dd19efcbf743b931379fa4cfd5f720a310f5b5f8db24d44a1d7b80ec0