Malicious PDF — malware analysis report

Static analysis result for SHA-256 88400eebc4e8f307…

MALICIOUS

PDF

80.5 KB Created: 2021-09-19 03:32:48 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 67a9bc9558ea65083193fa5a7805c5b5 SHA-1: 2e866c7c0fb149d7c7deb8d33e0096b3e31a8c48 SHA-256: 88400eebc4e8f307b4cb61d93f8c9fd95f96fc340bf884bc7111c361147c5cca
126 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many pointing to external PDF files on distinct domains, indicating a link farm. The 'PDF_SEO_DISPOSABLE_LINK_FARM' heuristic and the high ML score strongly suggest malicious intent, likely for phishing or distributing further malware. ClamAV also detected it as a phishing trojan.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9917

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://kaptenhoki.net/contents/files/vejidezuzotakeweki.pdf In PDF document text
    • https://asiantms.com/ckfinder/userfiles/files/givibuxebonesezexomufabu.pdfIn PDF document text
    • https://hkbca.org/UploadFiles/file/20210904195900195.pdfIn PDF document text
    • http://archiw.gbpopatowiec.pl/img/upload/files/dowuvaki.pdfIn PDF document text
    • http://studiogiamberardino.it/userfiles/files/roxoxipevo.pdfIn PDF document text
    • https://chambres-lannion.fr/userfiles/file/sebakamidifejudoduriz.pdfIn PDF document text
    • https://jjcfurnituremaker.com/userfiles/files/saxewijonabigijirilonut.pdfIn PDF document text
    • http://rosesrealtyhomes.com/userfiles/files/sowidosumulofeporolajugiv.pdfIn PDF document text
    • http://t-eamplus.de/web/editor/files/70779476047.pdfIn PDF document text
    • https://dukra.sk/editor_uploads/files/wobiramupumeset.pdfIn PDF document text
    • http://prasongp.com/file_media/file_image/file/25085995690.pdfIn PDF document text
    • http://lpxs168.com/filespath/files/20210916185042.pdfIn PDF document text
    • http://webspace.mysdam.net/images/newsletter/files/27370514180.pdfIn PDF document text
    • http://kehlux.lu/userfiles/files/nufaponevejovujuguse.pdfIn PDF document text
    • http://www.somdattabasu.com/fckimages/file/48950252602.pdfIn PDF document text
    • http://www.somdattabasu.com/fckimages/file/vulixit.pdfIn PDF document text
    • https://www.kadinlarsitesi.org/wp-content/plugins/formcraft/file-upload/server/content/files/1613166f8ac3b6---vokapamonabo.pdfIn PDF document text
    • http://sgyscom.com/upload_fck/file/2021-9-2/20210902104453356329.pdfIn PDF document text
    • http://80tner.friend-match.com/upload/files/gewifam.pdfIn PDF document text
    • http://i-dron.cz/data/file/12069740419.pdfIn PDF document text
    • https://prolocolidodisavio.org/ckfinder/userfiles/files/keluvitasijekoredadilele.pdfIn PDF document text
    • http://batterseataxi.com/survey/userfiles/files/17784302771.pdfIn PDF document text
    • https://bkairconditioner.cloud4demo.com/uploads/files/44262335984.pdfIn PDF document text
    • http://thechelseaff.com/user_uploads/files/98029955347.pdfIn PDF document text
    • http://www.introspekta.si/ckfinder/ckeditor_uploaded_files/files/tidopopuruf.pdfIn PDF document text
    • http://daiichihr.com/uploads/news_file/tolusifudegu.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/fzgW7-mxBc0/uplcv?utm_term=procreate+apk+modPDF 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_off0000d5b5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD5B5 10356 bytes
SHA-256: e3362d20c1c6dce84acf5b530ee2dae0bbfe7e10054e2be1f067902fd1e25ba5
font_01_sfnt_off0000ed22.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED22 18364 bytes
SHA-256: 0a822296fb66480da2387fcf2f92491cb23903ca6040795272646c8e845d1613
font_02_sfnt_off00011c62.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11C62 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1