Malicious PDF — malware analysis report

Static analysis result for SHA-256 4021e0cfc9713e87…

MALICIOUS

PDF

99.9 KB Created: 2021-10-16 05:56:55 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-22
MD5: e1abe361970d0f4347cd33441923049f SHA-1: 281f49be2ccb4fdeafceb5e67d915e62e755f8bb SHA-256: 4021e0cfc9713e8737e6c0e4f37a05f6f62d27ba4dec4ec2dbbbc9d75539dab8
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm with numerous distinct hosts, suggesting a phishing or malware distribution scheme. While no scripts were directly extracted, the PDF structure and external URI firings point towards the exploitation of user trust to redirect them to potentially harmful sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9875

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://sportuna.be/ckfinder/userfiles/files/mitizine.pdf In PDF document text
    • https://bank-kredit.at/ckfinder/userfiles/files/sapepe.pdfIn PDF document text
    • http://seoulmenu.com/uploads/files/mijelozebojugapu.pdfIn PDF document text
    • https://macauroommate.com/ckfinder/userfiles/files/xapekusotuvamorazepaf.pdfIn PDF document text
    • https://griby.biz/ckfinder/userfiles/files/54866248265.pdfIn PDF document text
    • http://taiwangallant.com/uploads/files/202109120508487131.pdfIn PDF document text
    • http://www.otevrenysklep.cz/ckfinder/userfiles/files/95876888220.pdfIn PDF document text
    • http://dinskayarealty.ru/media/file/75881514186.pdfIn PDF document text
    • http://elskup.pl/images/assets/file/wuxupipiwe.pdfIn PDF document text
    • http://acudrved.com/ckfinder/userfiles/files/17789160504.pdfIn PDF document text
    • https://djecijagarderoba.me/userfiles/file/nelunosefewagor.pdfIn PDF document text
    • http://biometria.pl/photos_fck/file/kasipurixipavuzolebepepa.pdfIn PDF document text
    • https://biomisszio.hu/tmp/javavapigiw.pdfIn PDF document text
    • http://telekommarketing.com/firme_data/files/65300027601.pdfIn PDF document text
    • http://hanauhrova.cz/files/digubutunegedimetepepe.pdfIn PDF document text
    • http://nghieuphong.com/upload/files/jozoxakiwa.pdfIn PDF document text
    • https://wacee.net/wp-content/plugins/formcraft/file-upload/server/content/files/161437d7f881b5---jagatanasup.pdfIn PDF document text
    • http://burattinojatek.hu/userfiles/file/72794214595.pdfIn PDF document text
    • https://genesisbehaviorcenter.com/wp-content/plugins/super-forms/uploads/php/files/e9907aefde83032dfe367b3285a202dc/rukibemizekerebo.pdfIn PDF document text
    • https://gancza-yacht.pl/userfiles/file/woligazudixu.pdfIn PDF document text
    • http://norrlandet.se/userfiles/file/77730552063.pdfIn PDF document text
    • http://siltherm.com/ckfinder/userfiles/files/25019748616.pdfIn PDF document text
    • http://imailbox.nl/images/uploadedimages/file/bamejaxumoralofowuxinebev.pdfIn PDF document text
    • http://creativecoms.net/userfiles/file/kubaxigo.pdfIn PDF document text
    • https://skvacations.com/userfiles/file/26045698523.pdfIn PDF document text
    • http://xdata.pl/app/webroot/img/ckf/files/nuzukulosanoraxagopiw.pdfIn PDF document text
    • http://feedproxy.google.com/~r/Xvkpad/~3/1hHberoKktI/uplcv?utm_term=arial+and+helveticaPDF 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_off00012363.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12363 10228 bytes
SHA-256: fef771971651b9f131fca5603f07ce0559c719894ea47452282ef7c36029d738
font_01_sfnt_off00013a37.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13A37 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00015249.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15249 18088 bytes
SHA-256: cbea780ca3be07365c8f1e99cc056feb2581cd8d8fc01024863af5b40e9fe8ff