Malicious PDF — malware analysis report

Static analysis result for SHA-256 37fcb8c617c325a7…

MALICIOUS

PDF

83.8 KB Created: 2021-09-18 07:11:37 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 18a9244d4f010b8b434bfb23bd8a5d74 SHA-1: 1dbebaa18147875e7f71a291e0cca73c195c4281 SHA-256: 37fcb8c617c325a7cb68294be82e404bb74c729976105c392f57a0e42718c07e
174 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The sample is a PDF file flagged by ClamAV as malicious and by an ML classifier. It contains embedded JavaScript and numerous external URIs, many of which are associated with link farms. The 'SE_BROWSER_INSTALL_LURE' heuristic indicates the document likely prompts the user to install a browser extension or update, a common tactic for malware delivery or credential harvesting. The embedded JavaScript suggests potential for further malicious actions, such as downloading and executing additional payloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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
  • Browser extension / update installation lure high SE_BROWSER_INSTALL_LURE
    Document tells the user to install a browser extension, plugin, viewer, or browser update to view content — a common social-engineering path for credential theft and malware installation
  • 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 http://datcat.vn/2018/file/barunotuvexof.pdf In PDF document text
    • http://msslink.ru/userfiles/files/50485494911.pdfIn PDF document text
    • https://receptabc.hu/images_banner/files/11343907912.pdfIn PDF document text
    • https://novitas.ro/files/rolotekafan.pdfIn PDF document text
    • http://theffirm.com/userfiles/file/tazusijiv.pdfIn PDF document text
    • http://agataklimowska.pl/userfiles/file/gogep.pdfIn PDF document text
    • http://kwik-it.ru/wp-content/plugins/formcraft/file-upload/server/content/files/161314588f0924---5656447693.pdfIn PDF document text
    • https://ibliberia.com/ckfinder/userfiles/files/fafem.pdfIn PDF document text
    • http://bukvoznaika.ru/ckfinder/userfiles/files/83219994972.pdfIn PDF document text
    • http://22vek-omsk.ru/fck_editor_files/files/lulopi.pdfIn PDF document text
    • http://xn----7sbbgprpk7biiq.xn--p1ai/admin/ckfinder/userfiles/files/59491823023.pdfIn PDF document text
    • https://rwd.webseo.tw/upload/files/kadunenufe.pdfIn PDF document text
    • https://www.restaurant-latableedevercel.com/ckfinder/userfiles/files/bopudikilasorumux.pdfIn PDF document text
    • http://cesnek-vysocina.cz/UserFiles/File/74924580658.pdfIn PDF document text
    • https://coopinproject.eu/ckfinder/userfiles/files/kilop.pdfIn PDF document text
    • https://iuoshili.com/upload/users/files/zegetosobuvazixewubigofo.pdfIn PDF document text
    • https://eghamatkade.com/basefile/eghamatkadecom/files/43380738629.pdfIn PDF document text
    • https://mandarinusa.com/userfiles/file/1631608033.pdfIn PDF document text
    • https://www.area-tlc.com/public/ckfinder/userfiles/files/32290605386.pdfIn PDF document text
    • http://plenerowe.kbo.pl/ckfinder/userfiles/files/selewenasugetivikixuleb.pdfIn PDF document text
    • http://mmsmarin.com/imgimage/file/93291926251.pdfIn PDF document text
    • https://ldcpc.com/ckfinder/userfiles/files/84908508070.pdfIn PDF document text
    • http://gunjanjain.com/app/webroot/js/uploads/files/doteji.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/LPIa9PGmDLg/uplcv?utm_term=prince+of+persia+ms+dos+downloadPDF 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_off0000de63.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDE63 19260 bytes
SHA-256: 0acdd6d894d30b542a4c09385f0b812790c5aac74f00acf57f1272952a215867
font_01_sfnt_off00011096.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11096 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000128ad.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x128AD 10768 bytes
SHA-256: baa98488bfb1616112b7da44d1ecb9c67b021224930c7bed12b5529cda441de0