Malicious PDF — malware analysis report

Static analysis result for SHA-256 23d40aebdc8abf4e…

MALICIOUS

PDF

85.8 KB Created: 2021-09-16 03:48:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: c823e47250296d17e4da6be68de07b1f SHA-1: c68c6ed0b71c93b862b5d6d756882f1916cf733b SHA-256: 23d40aebdc8abf4eeb333074191a99628b3cbffd6f6c97eb52b60561d6825e7f
134 Risk Score

Malware Insights

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

The PDF was flagged by multiple heuristics, including a critical ClamAV detection for 'Pdf.Phishing.Trojan'. The presence of numerous external URIs, many pointing to disposable hosting and employing UTM parameters, suggests a link farm designed to redirect users. The ML classifier output of 0.99 further supports its malicious nature, likely as a phishing lure to download additional payloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9912

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
  • 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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://huntic.ru/uplcv?utm_term=multiplayer+horror+games+offline PDF link annotation
    • https://webhostmurah.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613a151ccb476---8696354901.pdfIn PDF document text
    • http://sea-cruise.ru/ckfinder/userfiles/files/57875734408.pdfIn PDF document text
    • http://uspeh-kursk.ru/ckfinder/userfiles/files/10869344898.pdfIn PDF document text
    • http://whuntex.info/userfiles/file/wozemij.pdfIn PDF document text
    • https://imihwa.com/uploads/image/20210910/files/20210910101304.pdfIn PDF document text
    • http://darec.sk/files/files/6100941110.pdfIn PDF document text
    • http://electronicaindex.nl/images/uploads/17554527807.pdfIn PDF document text
    • http://kcntanduc.vn/img_duhoc/files/26213966331.pdfIn PDF document text
    • http://open.ua/uploads/ckeditor/files/9003501489.pdfIn PDF document text
    • https://calienglish.com/ckfinder/images_store/files/55244141113.pdfIn PDF document text
    • http://satcomlink.com/userData/board/file/74269281976.pdfIn PDF document text
    • https://oddluzanie.net/userfiles/file/fixan.pdfIn PDF document text
    • http://thriftstorewebsites.com/flash/thriftstorewebsites.com/file/63762006508.pdfIn PDF document text
    • http://beerskiboot.com/img/upload/file/69482352078.pdfIn PDF document text
    • http://cablexconsulting.com/Upload/file/roweber.pdfIn PDF document text
    • http://oikoscoccatoarchitettura.com/userfiles/files/16868972477.pdfIn PDF document text
    • http://china-miyaco.com/img/file/20219911021.pdfIn PDF document text
    • https://www.nvsrolko.org/ckfinder/userfiles/files/vimofiwujigesematobo.pdfIn PDF document text
    • http://briztravel.com/upload/files/85051493376.pdfIn PDF document text
    • https://wotfiles.com/ckfinder/userfiles/files/pevedidokazok.pdfIn PDF document text
    • http://musik-fachberatung-neumarkt.de/images/uploadedimages/file/7817649340.pdfIn PDF document text
    • https://allcreaturesinc.com/files/files/nixefuzutudiwufigadewa.pdfIn PDF document text
    • http://global-leasing-management.com/uf/file/fetunalub.pdfIn PDF document text
    • https://thebottombillion.org/business_school/uploads/file/93499722150.pdfIn PDF document text
    • http://toptoptraining.ru/img/upload/file/83708026318.pdfIn PDF document text
    • http://aaykpn.com/uploads/editor/files/10254403046.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_off0000ea3b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEA3B 17344 bytes
SHA-256: 8ec368df9be3b4152c7d6eb70bb31bf51d49a64bea840b35279ca83e516171f3
font_01_sfnt_off00011750.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11750 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012f67.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12F67 11012 bytes
SHA-256: f5e8271347b8714397e682370928eb9f0a9504dd0510426cb54c5c90a706d848