Malicious PDF — malware analysis report

Static analysis result for SHA-256 b4ee5e164db99501…

MALICIOUS

PDF

82.6 KB Created: 2021-09-15 02:26:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-04
MD5: 3c585de56d956b5fc74b8c267fa3cb5b SHA-1: f6ba82e8ed69d89de456b6f292962d08f582caef SHA-256: b4ee5e164db995016429b647a33d808406fc17ed79cd595ec23ff27351f0175d
166 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF document was flagged as malicious by ClamAV and an ML classifier. The file embeds a large number of external links characteristic of an SEO link farm. Specific URLs and indicators for this sample are listed in the indicators section.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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
  • PDF link to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://smidgel.ru/uplcv?utm_term=8th+social+studies+textbook PDF link annotation
    • http://spbmedaks.ru/sites/default/files/uploads/movunefer.pdfIn PDF document text
    • http://odnoklassniki-files.ru/images/uploads/files/89454016943.pdfIn PDF document text
    • http://vansuloi.com/uploads/userfiles/file/14343980168.pdfIn PDF document text
    • https://highfieldhousehotel.net/nbloom/fckuploads/file/wiviloxibadenaxuserave.pdfIn PDF document text
    • https://textosolutionslinguistiques.ca/upload/editor/file/57583901742.pdfIn PDF document text
    • http://ewhamd.net/upFiles/ckeditor/files/xefugenavuduwere.pdfIn PDF document text
    • https://gelblighting.com/userfiles/files/feninawafefuribijak.pdfIn PDF document text
    • http://kitpaisal.com/mypicture/file/74709403024.pdfIn PDF document text
    • http://ekmeta.lt/failai/file/videla.pdfIn PDF document text
    • http://jeanthompson.nl/ckfinder/userfiles/files/piseroraviruwovesagatikeg.pdfIn PDF document text
    • http://skkl.cn/filespath/files/20210902055546.pdfIn PDF document text
    • http://mega.kz/media/upload/files/tijuvoda.pdfIn PDF document text
    • https://childrencareandliteracysociety.org/userfiles/files/dibiwuresokizomikunad.pdfIn PDF document text
    • http://patanjali.zohukum.com/ckfinder/userfiles/files/sotutovobamex.pdfIn PDF document text
    • https://kaparatt.com/images/File/tovunidasebozaliz.pdfIn PDF document text
    • http://windowsplusllc.com/ckfinder/userfiles/files/joguvipovibunifiwur.pdfIn PDF document text
    • http://hwayoung.kr/upfile/files/16798289142.pdfIn PDF document text
    • https://cosonnguyenthanh.vn/webroot/userfiles/files/63638547104.pdfIn PDF document text
    • http://dgkno.cn/upload/jasabagezepatipam.pdfIn PDF document text
    • http://www.platformliften.info/wp-content/plugins/formcraft/file-upload/server/content/files/16130726cc01c8---gokuxir.pdfIn PDF document text
    • http://mariamozharova.ru/uploads/files/64540150816.pdfIn PDF document text
    • https://xylemleads.com/userfiles/file/sujukoxabotowelajuguxowev.pdfIn PDF document text
    • http://somsit.com/ckfinder/userfiles/files/27681611819.pdfIn PDF document text
    • http://paradisoseminatrici.it/userfiles/files/57957823206.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_off0000df21.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDF21 17104 bytes
SHA-256: eb5981fffcd548e6bad0c3a922713fc2442860642cf353aaea7bfebff318b709
font_01_sfnt_off00010b3d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10B3D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012354.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12354 10808 bytes
SHA-256: 8f7e0d65bc762165f6dc04e68ffab05e6a2212f1578603de4af1caef6a7172e7