Malicious PDF — malware analysis report

Static analysis result for SHA-256 231cd8be65dec97a…

MALICIOUS

PDF

79.5 KB Created: 2021-09-07 01:53:37 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-22
MD5: 8953d2f5e5340c752d126a19db2823b5 SHA-1: f1f56a9175982c3ffdedc6e274a8673baafe7c69 SHA-256: 231cd8be65dec97aff3c886bba0ff36facc2761b8d65ae1df3f6653fe90d2d5f
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF containing embedded JavaScript, which is a common technique for delivering malicious content. The PDF also contains numerous links to external websites, many hosted on compromised or disposable domains, suggesting a link farm designed to redirect users to malicious sites. The ClamAV detection and ML classifier strongly indicate malicious intent, likely for phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9960

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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://maugli24.ru/wp-content/plugins/super-forms/uploads/php/files/19fe41767a1a66cb6a21d08779f562b7/94422151556.pdf In PDF document text
    • https://laughteronlineuniversity.com/images/upload/files/67996523644.pdfIn PDF document text
    • http://grubstreet.ca/ckfinder/userfiles/files/27296347288.pdfIn PDF document text
    • http://mackyz7automotive.com/js/upload/files/43780232178.pdfIn PDF document text
    • https://yuktiedu.com/wp-content/plugins/super-forms/uploads/php/files/e86e6519c095528d1318d6f981aafa55/95756084393.pdfIn PDF document text
    • http://aczelzalog.hu/tmp/45933438785.pdfIn PDF document text
    • https://ehblending.com/wp-content/plugins/super-forms/uploads/php/files/fd6bf1b37a1f43ad21bf911b4899eec5/29069257699.pdfIn PDF document text
    • http://brmxn.com/userfiles/file/20210707043115_dsee3y.pdfIn PDF document text
    • https://ou-ravda.com/ckfinder/userfiles/files/90364997365.pdfIn PDF document text
    • http://kleinschadenexperte.de/userfiles/file/67987256519.pdfIn PDF document text
    • https://livre-d-art.com/ckfinder/userfiles/files/14931322922.pdfIn PDF document text
    • https://flexi-cms.com/uploads/file/rukipabarobibudi.pdfIn PDF document text
    • https://alpinashop.bg/files/19171666588.pdfIn PDF document text
    • http://ophtalmic-overnight.fr/wp-content/plugins/formcraft/file-upload/server/content/files/1609f9fd04cb5e---83284390873.pdfIn PDF document text
    • http://bronia.org/userfiles/file/dukasurejuja.pdfIn PDF document text
    • https://www.bnbtravels.com/ckfinder/userfiles/files/15397214668.pdfIn PDF document text
    • http://www.facyt.com.ar/ckfinder/userfiles/files/fibipeguju.pdfIn PDF document text
    • https://barcelonacentromedico.es/files/galeria/files/87504680654.pdfIn PDF document text
    • http://kommunikator.nu/demo/userfiles/file///pizusotorapufinitor.pdfIn PDF document text
    • http://bassbasement.org/userfiles/file/10155066184.pdfIn PDF document text
    • https://stefandes.com/wp-content/plugins/formcraft/file-upload/server/content/files/16084b91f525c9---44083631353.pdfIn PDF document text
    • http://zzweien.com/d/files/tunogesuzeputuveniwoz.pdfIn PDF document text
    • http://slp61.com/clients/e/e2/e296dcecfd7d10ffef0cc83fef253c72/File/71436342503.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/LPIa9PGmDLg/uplcv?utm_term=substance+use+disorders+pdfPDF 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_off0000d373.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD373 17024 bytes
SHA-256: 2184190e9fafb36790e8c00e8ccb814f430f89b9e82ff42169f2c34acb967118
font_01_sfnt_off0000ffbf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFFBF 10880 bytes
SHA-256: b6a4d18f20108e25b3edce6b8b19d749dac9a24c25f49aaa5f7da45cec9a7236
font_02_sfnt_off000118d3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x118D3 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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