Malicious PDF — malware analysis report

Static analysis result for SHA-256 16c481d3a8dc230c…

MALICIOUS

PDF

71.6 KB Created: 2021-10-09 22:25:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: 418e6688236da22d00f882f98e90a01f SHA-1: da1487af24774caef1c5d942c356e24be3ba94bb SHA-256: 16c481d3a8dc230c67f76a2a04fcb77a6fce1f78f5de365d2edfbaf79ce2419a
74 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains embedded JavaScript, a common technique for executing malicious code within documents. The ML classifier strongly indicated maliciousness. The sample also exhibits characteristics of a link farm, with numerous external URLs pointing to PDF files, suggesting a potential phishing or malware distribution campaign. The embedded JavaScript likely facilitates the redirection to these external resources.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 5

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://itandem.net/ckfinder/userfiles/files/jifusereruputowudafej.pdf In PDF document text
    • http://thanhnienxp.com/vietkiendo/upload/file/50217375549.pdfIn PDF document text
    • http://dekobonner.de/userfiles/file/57032678504.pdfIn PDF document text
    • http://combatkuntao.com/ckeditor/ckfinder/userfiles/files/24337405302.pdfIn PDF document text
    • http://khojedu.net/userfiles/file/xubixewujam.pdfIn PDF document text
    • http://apsons.eu/files/file/wixonavezebedixikozetovum.pdfIn PDF document text
    • http://luluscafeonline.com/uploads/files/95387534706.pdfIn PDF document text
    • http://ljjxmining.com/uploadfile/file///2021092909562970.pdfIn PDF document text
    • http://hak-al.com/resimler/files/zewewa.pdfIn PDF document text
    • http://www.kizkulesikizogrenciyurdu.com/public/ckfinderuploads/files/6599576417.pdfIn PDF document text
    • https://diedacorporation.net/freesiafiles/file/10369692108.pdfIn PDF document text
    • http://www.ccengis.be/applications/ckeditor/addons/ckeditor/ckfinder/userfiles/files/midagapademu.pdfIn PDF document text
    • http://rulife.ru/ckfinder/userfiles/files/93387533701.pdfIn PDF document text
    • http://rasciindia.com/firetech/ckupload/files/78310000180.pdfIn PDF document text
    • http://furkansigorta.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/1615f95909db0b---puzufeturizutegadowigil.pdfIn PDF document text
    • https://conexus-study-abroad-travel.com/ckfinder/userfiles/file/tesezalaxixelavijazet.pdfIn PDF document text
    • http://rgn2u.com/userfiles/files/87982814635.pdfIn PDF document text
    • https://radmangroup-ye.com/rgfiles/file/31703096795.pdfIn PDF document text
    • http://cleanyachts.it/writable/public/userfiles/file/33056489711.pdfIn PDF document text
    • http://bookblog.kr/data/file/files/69162044875.pdfIn PDF document text
    • https://www.travelknowhowscotland.co.uk/assets/js/ckfinder/userfiles/files/28734414539.pdfIn PDF document text
    • http://kaizousha.com/js/upload/files/fepiwazekem.pdfIn PDF document text
    • http://sbkf.org/files/files/49768074145.pdfIn PDF document text
    • http://mfo-fond.ru/ckeditor/ckfinder/userfiles/Images/files/monifajupanod.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/FevRqgeaUVY/uplcv?utm_term=how+many+days+pregnant+is+full+termPDF link annotation
    • https://lapdonline.org/file/todisekiligez.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_off0000b694.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB694 15772 bytes
SHA-256: fc09ad153eb8be0d892624f4bdc184c15f7bb76a51d20f2736eb5ffbc1788062
font_01_sfnt_off0000de86.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDE86 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f69d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF69D 11132 bytes
SHA-256: 4bde4f7bee76d81bf749ffb6be1f29978d8ebffeb782eaef595fcfc63750943e