Malicious PDF — malware analysis report

Static analysis result for SHA-256 51bdab63c95505d1…

MALICIOUS

PDF

90.1 KB Created: 2021-09-16 04:36:09 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 93f84aceb106933100fe6587bbb719d7 SHA-1: 269e90e99ecb12394196c1580a1ac9998c291cfa SHA-256: 51bdab63c95505d1e46d01eaa67d19d1d06a4696c66c59fdbedea86f63ec2ce5
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains a large number of external links, many pointing to compromised websites or disposable hosting, indicating a link farm designed to distribute malicious content or phish users. The ML classifier and ClamAV detection strongly suggest malicious intent. Although no scripts were explicitly extracted, the PDF structure and link farm behavior are indicative of a malicious document, likely delivered as a spearphishing attachment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9982

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
  • 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.
  • 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://ketchas.ru/uplcv?utm_term=beetlejuice+full+movie+123 PDF link annotation
    • http://beijingxinzhi.com/userfiles/file/20210906205556_1397190761.pdfIn PDF document text
    • http://ontheedgeofnow.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614152c0e49ea---gefurowukufag.pdfIn PDF document text
    • https://arhstroi.by/uploads/files/mixuruz.pdfIn PDF document text
    • http://www.ktgroup.co.uk/ckfinder/userfiles/files/faxajarojagimifowaxef.pdfIn PDF document text
    • http://naturenhuman.com/app/webroot/userfiles/file/5956490838.pdfIn PDF document text
    • https://www.d-table.com/wp-content/plugins/super-forms/uploads/php/files/0a274866fd7ea2957690b4aee7a846a2/66025986704.pdfIn PDF document text
    • https://glass-haus.ru/wp-content/plugins/super-forms/uploads/php/files/03d2bec32f4e7e5662367ee65d49c172/baneburemodivevumukaludos.pdfIn PDF document text
    • https://k-kompany.ru/wp-content/plugins/super-forms/uploads/php/files/7993f66d498aecd1ee12c02f3532303c/sukikul.pdfIn PDF document text
    • http://airmon.hu/images/files/32670336258.pdfIn PDF document text
    • https://cardion.dk/gfx/fckimages/file/52345145178.pdfIn PDF document text
    • http://sakuragiramenandsushi.com/uploads/files/98579887140.pdfIn PDF document text
    • https://callmarkinvestments.com/callmark/files/91364036133.pdfIn PDF document text
    • https://thegioibaobicarton.com/Images_upload/files/vejeviwefuri.pdfIn PDF document text
    • http://gianniarnaudo.com/userfiles/files/89611330379.pdfIn PDF document text
    • http://kleinschadenexperte.com/userfiles/file/wawixabetasi.pdfIn PDF document text
    • https://pratham.one/file/lirefevir.pdfIn PDF document text
    • https://jasz-pap.hu/UserFiles/file/dedojaluwujati.pdfIn PDF document text
    • http://szzxwx.com/Upload/Upload/file/20219551622656.pdfIn PDF document text
    • http://righetti-ticozzi.it/userfiles/files/tiradigusonuzimodowixate.pdfIn PDF document text
    • http://ristorantebiscione.com/userfiles/files/lulutepituro.pdfIn PDF document text
    • http://pronobile.de/catalog/file/gulugomug.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_off0000ef91.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEF91 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off000107a8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x107A8 10656 bytes
SHA-256: 347ba6e337d8644161f5c1c0727dde65dd8050bd0b851b085fd211b5721f40c3
font_02_sfnt_off00012038.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12038 22000 bytes
SHA-256: e52d0266c0bbd782108e08133a60514e88733d23c363e30bf8f5ece77370f878