Malicious PDF — malware analysis report

Static analysis result for SHA-256 18c70b920cdda5fd…

MALICIOUS

PDF

70.4 KB Created: 2021-09-16 07:55:04 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 8d9bfb9cf2c2a3973424dde40a0c70cf SHA-1: 638aac21c7274f302de3bc4fe8a2fadf21bc8e17 SHA-256: 18c70b920cdda5fdc54f5e2fae20b537d9c0e10fc095bbeed1e61b49286e863c
134 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains embedded JavaScript and a large number of external URIs, many of which are part of a link farm on disposable hosting. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware via the embedded links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

Heuristics 6

  • 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.
  • 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://crewmak.ru/uplcv?utm_term=interactive+operating+system+example PDF link annotation
    • https://testagenda1.myagenda.cz/pictures/editor/files/51345348978.pdfIn PDF document text
    • http://isleford.com/filespath/files/20210916080233.pdfIn PDF document text
    • https://markaoyun.com/calisma2/files/uploads/jixojisosokibigajipa.pdfIn PDF document text
    • http://aftp.bg/userfiles/file/xuxunijivewudetijobujinoz.pdfIn PDF document text
    • http://thetestmag.com/userfiles/files/90358835982.pdfIn PDF document text
    • https://www.lipca.com/ckfinder/userfiles/files/12489863877.pdfIn PDF document text
    • https://pataniforum.com/admin/jquery/ckfinder/userfiles/files/96146536547.pdfIn PDF document text
    • https://asztromiskolc.hu/ckfinder/userfiles/files/97812464597.pdfIn PDF document text
    • https://y3stwk65l-mn9.com/contents/files/20669251240.pdfIn PDF document text
    • http://www.letnifestiwal.pl/ckfinder/userfiles/files/31611519575.pdfIn PDF document text
    • http://krukaiart.com/userfiles/files/rejewafaxanurabigoxi.pdfIn PDF document text
    • https://viettincapital.vn/upload/files/jixepafazapov.pdfIn PDF document text
    • http://giadinhlaurenso.org/upload/files/keforokod.pdfIn PDF document text
    • http://hoteldanang.vn/uploads/images/files/81717774900.pdfIn PDF document text
    • http://artsar.pl/userfiles/file/83055992545.pdfIn PDF document text
    • http://www.itbaloch.com/wp-content/plugins/formcraft/file-upload/server/content/files/16138b90a7ed9f---25859562741.pdfIn PDF document text
    • https://dpengineers.info/admin/userfiles/file/85667332718.pdfIn PDF document text
    • http://dfwsedan.com/nbloom/fckuploads/file/67213164933.pdfIn PDF document text
    • http://eclickapps.in/userfiles/files/bajibuzeje.pdfIn PDF document text
    • https://avflash.nl/upload/files/70357564674.pdfIn PDF document text
    • https://houstoncoinclub.org/FCKeditor/file/juxidukogaz.pdfIn PDF document text
    • http://www.masozilina.sk/ckfinder/userfiles/files/97714330916.pdfIn PDF document text
    • https://www.assessment.unibe.ch/app/webroot/js/ckfinder/userfiles/files/vujagamelozonedokogidipog.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_off0000b356.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB356 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000cb68.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCB68 15392 bytes
SHA-256: 437b6efdd7e948bb9aaf1bab731709e7bc1a69583e344f5d3969dfca007992e7
font_02_sfnt_off0000f2a5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF2A5 10948 bytes
SHA-256: 792c16f8ff4fec37d7056390870a0e79d89a978bd4e9012821febae4a98fc79c

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