Malicious PDF — malware analysis report

Static analysis result for SHA-256 b537080859e1eb4b…

MALICIOUS

PDF

79.1 KB Created: 2021-09-16 18:13:21 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-23
MD5: 9c0c8d22ec973bbe07043a8e8f789d5c SHA-1: 6a03728470f11fa31e04f0e461dc64bc62d26349 SHA-256: b537080859e1eb4b632aee90a4abea3d13d95ae0427217051db0476d8986f381
126 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, directing users to multiple disposable domains, with one primary PDF link identified as potentially malicious. The document body is heavily obfuscated and unreadable, suggesting it's not intended for human consumption but rather to host links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

Heuristics 5

  • 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.
  • 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://gilbertems.com/videos/file/87414810646.pdf In PDF document text
    • http://monterroso-construpuntos.com/campannas/file/84199975612.pdfIn PDF document text
    • http://studioingegneramato.com/userfiles/files/27188949840.pdfIn PDF document text
    • http://tourhong.com/FileData/ckfinder/files/20210911_1814E85937E918AC.pdfIn PDF document text
    • http://saltokisport.com/uploads/files/pinifapifu.pdfIn PDF document text
    • https://alley.52886.tw/uploads/files/rijafarojidebadakone.pdfIn PDF document text
    • https://www.wizzfizz.com.au/application/third_party/ckfinder/userfiles/files/latewuralodepodeb.pdfIn PDF document text
    • http://iccjsc.com/images/uploads/files/91269382032.pdfIn PDF document text
    • http://rwdwebwebdesign.com/img-aim/files/xopedavozetoduz.pdfIn PDF document text
    • https://tp-pos.com/uploads/image/files/20936571390.pdfIn PDF document text
    • https://kfk-dekoration.dk/images/uploadedimages/file/74853002248.pdfIn PDF document text
    • https://kohphanganhotelandtour.com/userfiles/file/buvubowurorudisivozukevop.pdfIn PDF document text
    • http://medicapoland.pl/uploaded/file/75572812603.pdfIn PDF document text
    • http://imobilestore.de/userfiles/file/46072008798.pdfIn PDF document text
    • https://www.hkha.com.hk/ckfinder/userfiles/files/xiludujiserokalotasit.pdfIn PDF document text
    • https://kimcert.com/E/file/limemasi.pdfIn PDF document text
    • http://hmed.vn/upload/files/davaku.pdfIn PDF document text
    • http://kapfenberger-schuetzenverein.at/userfiles/file/41425390860.pdfIn PDF document text
    • https://toliveinchristjesus.ceosale.catholic.edu.au/application/third_party/ckfinder/userfiles/files/42935260383.pdfIn PDF document text
    • https://durgabas.coop.np/ckfinder/userfiles/files/zejatunutofuk.pdfIn PDF document text
    • https://glosunspa.com/wp-content/plugins/formcraft/file-upload/server/content/files/16131f411432b7---66027330453.pdfIn PDF document text
    • https://melnikhouse.com/userfiles/file/60354708206.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/DOqCt-cVA4I/uplcv?utm_term=paper+minecraft+crafting+guidePDF 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_off0000d0f4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD0F4 17532 bytes
SHA-256: 088fd7665863f90f884a8228cd93311aac6df679d7affe9809c271d3c205e7ba
font_01_sfnt_off0000fe93.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFE93 10732 bytes
SHA-256: 8466d64466fab4066c709e9571807d3b3c35b2354f2f7a0577b33d754ec28610
font_02_sfnt_off00011707.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11707 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1