Malicious PDF — malware analysis report

Static analysis result for SHA-256 a8516d3c19e40bf9…

MALICIOUS

PDF

94.3 KB Created: 2021-09-15 17:58:01 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: f9d1c6e1b8be0606d498774dab79d52d SHA-1: 87ab79a1ccc21e379fc185f335c334a6d5d3a560 SHA-256: a8516d3c19e40bf9802805a3732f25c6f04615a6e48fe6c0dd885d0360fe9f71
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs, many of which are part of a link farm designed to obscure the ultimate destination, which appears to be a lure for a Chrome browser update. The presence of external URIs and the link farm structure strongly suggest a phishing or social engineering attack.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9969

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://pistant.ru/uplcv?utm_term=update+chrome+browser+on+android PDF link annotation
    • http://geopraxis.it/userfiles/files/54691010176.pdfIn PDF document text
    • http://sp2wronki.pl/fotki/fotki/file/leparoriwolo.pdfIn PDF document text
    • https://www.xyoaa.org/sites/default/files/files/28033691791.pdfIn PDF document text
    • http://cokhihoangvinh.com/uploads/userfiles/file/reponiruxeveniv.pdfIn PDF document text
    • http://hairtransplantmangalore.com/uploaded_files/userfiles/files/tipifugazisiwudunajodasif.pdfIn PDF document text
    • http://dakmet.pl/upload/bodatediki.pdfIn PDF document text
    • http://lingvastar.z-i-g-z-a-g.com/userfiles/files/xexidukik.pdfIn PDF document text
    • http://arcomproltd.com/userfiles/file/59227753426.pdfIn PDF document text
    • http://jwconsult2005.com/file_media/file_image/file/40974071085.pdfIn PDF document text
    • http://ybshajiang.com/userfiles/file/2021-09-04/2109042043257238217gdtrtxmnmk4.pdfIn PDF document text
    • http://sportsbettingconsultants.net/cote_dor_import/admin/ckfinder/userfiles/files/66136877918.pdfIn PDF document text
    • http://esipro.lu/userfiles/file/jamotibexonumomitavozi.pdfIn PDF document text
    • http://ppogrimall.com/upload/editor_image/file/rasefusefet.pdfIn PDF document text
    • http://castel.lu/userfiles/files/sepele.pdfIn PDF document text
    • http://nexxstep.nl/userfiles/file/nigevogumegoguxefijawulix.pdfIn PDF document text
    • https://santevita-bg.com/ckfinder/userfiles/files/duwanebilozovuzananejene.pdfIn PDF document text
    • https://bentzendesign.se/wp-content/plugins/formcraft/file-upload/server/content/files/161417dca88d95---9264177427.pdfIn PDF document text
    • http://baove24h.info/upload/files/meweku.pdfIn PDF document text
    • https://www.hippocratio.gr/ckfinder/userfiles/files/memevawisewuwede.pdfIn PDF document text
    • https://www.loisirs-auto-occasion.fr/ckfinder/userfiles/files/nalibarozede.pdfIn PDF document text
    • http://ipmarketing.net/FCKeditor/editor/filemanager/connectors/userfiles/file/82123307848.pdfIn PDF document text
    • https://www.kindspring.org/inc/ckfinder/userfiles/files/nuvapetevuva.pdfIn PDF document text
    • http://biondiairsystem.it/userfiles/files/92149572268.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_off00010752.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10752 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00011f69.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11F69 10968 bytes
SHA-256: 1719c925d254d141fc9831cc80042d196e3ddcb5b2e24773d0c82154a4cecc5a
font_02_sfnt_off00013887.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13887 19740 bytes
SHA-256: d1efe95a69d9639e8aa04e22574b8846031864ab9bbc6786f1c44885483d36bb