Malicious PDF — malware analysis report

Static analysis result for SHA-256 4c9c8381463b4eeb…

MALICIOUS

PDF

70.3 KB Created: 2021-09-18 10:55:48 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 23ac2bdfaafe8369c769264362f0a384 SHA-1: 2f308fde475de547359f42c203c8628087920708 SHA-256: 4c9c8381463b4eeb899ef18b96deeb8f0392473dc9ae65c5fe15b8cdabcdf457
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by multiple heuristics and a machine learning classifier as malicious, with ClamAV identifying it as a phishing trojan. The embedded URLs and the PDF structure indicate a link farm designed to redirect users to download potentially harmful files, such as the 'quik+full+apk' referenced in one URL. While no scripts were explicitly extracted, the PDF's nature and the numerous external links strongly suggest a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9947

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://cructi.ru/uplcv?utm_term=quik+full+apk PDF link annotation
    • https://cartolmania.it/file/80200765035.pdfIn PDF document text
    • http://smartraoptics.com/fck_filemanager_upload/file/vupejanup.pdfIn PDF document text
    • https://freedomtampons.com/wp-content/plugins/super-forms/uploads/php/files/ce97ad17b4f1096a71ad5c0192cd0d7a/89568188812.pdfIn PDF document text
    • http://zaragozalawoffice.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/13865585837.pdfIn PDF document text
    • http://ydtmuhendislik.com/ckfinder/userfiles/files/78327628907.pdfIn PDF document text
    • http://yuha.be/_files/file/serijexasijiwijademegaxo.pdfIn PDF document text
    • https://digireg.gr/upload/tatuzofujezatofuzov.pdfIn PDF document text
    • http://eau-msu.ru/ckfinder/userfiles/files/58751009918.pdfIn PDF document text
    • https://sunrise-photon.com/upfiles/editor/files/47060939677.pdfIn PDF document text
    • http://instalater-macecek.cz/klienti/devel/sneznerolby.cz/ckfinder/userfiles/files/56622160338.pdfIn PDF document text
    • http://backkwang.com/userData/board/file/46538765706.pdfIn PDF document text
    • https://espritgt.com/userfiles/file/pawuniporavejetujatulir.pdfIn PDF document text
    • http://studiocastigli.eu/userfiles/files/wurilejoweso.pdfIn PDF document text
    • https://valubil.com/public/uploads/cms_file/cms_files/28341849676.pdfIn PDF document text
    • https://kientrucqhouse.com/uploads/image/files/gipazuxoniram.pdfIn PDF document text
    • http://borneneskontor-landsforening.dk/userfiles/file/21268645841.pdfIn PDF document text
    • http://veganogle.es/uploads/ckfinder/files/82907170987.pdfIn PDF document text
    • https://pensionradvanice.cz/res/file/49689577263.pdfIn PDF document text
    • http://nhasachnguyenvancu.com/Images_upload/files/potisozusonesepepigafopa.pdfIn PDF document text
    • http://owv-sad.de/userfiles/files/vutidojizuguwokise.pdfIn PDF document text
    • https://www.generalutilities.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614469c85dd08---86204649027.pdfIn PDF document text
    • http://dietetyka-24.pl/images/files/mujux.pdfIn PDF document text
    • https://harmony-lazienka.pl/Upload/file/pefunuda.pdfIn PDF document text
    • http://top-rubber.com/admin/fckeditor/editor/filemanager/connectors/upload/file/65055439763.pdfIn PDF document text
    • http://plaschke-partner.com/uploaded/file/72281610060.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_off0000b428.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB428 16488 bytes
SHA-256: 4c0e26de72d67b54be565a3dcc65968efd2296233cc0377f154dbc3fc2f16118
font_01_sfnt_off0000de2d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDE2D 9880 bytes
SHA-256: 68186e95f7831c8f2e1cb213ff9507dca38e7b61ccb9bd5bd4ceeb586f1de80a
font_02_sfnt_off0000f412.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF412 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1