Malicious PDF — malware analysis report

Static analysis result for SHA-256 1998af44e4ffb143…

MALICIOUS

PDF

87.8 KB Created: 2021-07-23 21:43:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-13
MD5: d2fe367183c59769e8372ca1dbf5d44d SHA-1: 82f97564d9e96c2299a77127f4f91a6ed6669789 SHA-256: 1998af44e4ffb143db685700422f00a85ab06312c9bf0eeeb3d1cb997f1f2ad9
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF file contains a large number of embedded URLs, many of which point to compromised websites or disposable hosting, indicating a link farm. The ML classifier strongly flagged this PDF as malicious. While no scripts were extracted, the structure and numerous external links suggest it's designed to redirect users to potentially harmful content or exploit vulnerabilities.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

Heuristics 5

  • 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://kes-stv.ru/wp-content/plugins/super-forms/uploads/php/files/98d5d52807e7cf39e3d278f213866ed1/wefusevimigonegijupavenig.pdf In PDF document text
    • http://erkerlaender.de/wp-content/plugins/formcraft/file-upload/server/content/files/160779a4932e34---luzusavebotoduno.pdfIn PDF document text
    • http://ed-web.cz/userfilesfile/59937181707.pdfIn PDF document text
    • http://yorktownhs1987.com/clients/57482/File/42986967793.pdfIn PDF document text
    • http://tungalag.mn/userfiles/files/bigejixajadubejevogubad.pdfIn PDF document text
    • http://ciaooo.ru/uploades/userfiles/file/sefitetigafitezosevob.pdfIn PDF document text
    • https://www.lipfish.no/wp-content/plugins/formcraft/file-upload/server/content/files/160946a85f024a---wikometipibeb.pdfIn PDF document text
    • http://duszek-lasu.pl/userfiles/file/72101492982.pdfIn PDF document text
    • http://bettynblue.com/upload/fck_img/20210627/file/5948173857.pdfIn PDF document text
    • http://aiswaryamatrimonials.com/fck_uploads/file/96929810315.pdfIn PDF document text
    • https://www.toptalentusa.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b8406ecafe3---19131292253.pdfIn PDF document text
    • https://drainscovers.com/wp-content/plugins/super-forms/uploads/php/files/4698ebca915fe4ddb2f3bc9b363e586f/nifejizotubes.pdfIn PDF document text
    • http://graphicon.hu/wp-content/plugins/formcraft/file-upload/server/content/files/1607255275e262---xarabofijatutetizizukogon.pdfIn PDF document text
    • http://aiswaryamatrimonials.com/fck_uploads/file/26583833992.pdfIn PDF document text
    • http://supermarketdv.ru/files/file/88520115690.pdfIn PDF document text
    • http://pensionpoint.cz/userfiles/files/zotujuvamekojivanezoju.pdfIn PDF document text
    • https://skyfireconsulting.com/wp-content/plugins/super-forms/uploads/php/files/afpjnesf5ehfpilbuqo6jfe8vs/zonedorowerenamimo.pdfIn PDF document text
    • https://europeancustomtailor.com/wp-content/plugins/super-forms/uploads/php/files/cc37e5b72dc8b6f6bbbffad274180571/palobuwumon.pdfIn PDF document text
    • http://kursadowicz.pl/Upload/file/11092750655.pdfIn PDF document text
    • http://bukharaatlanta.com/sites/default/files/file/25354790369.pdfIn PDF document text
    • http://www.hkwebdesign.com.hk/wp-content/plugins/formcraft/file-upload/server/content/files/160ad14d196cde---56646552230.pdfIn PDF document text
    • https://thai-airpark.com/ckfinder/userfiles/files/77681182407.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/GLLx1DTH0VQ/uplcv?utm_term=free+gospel+music+downloads+for+android+phonesPDF 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_off0000f123.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF123 17348 bytes
SHA-256: 356e8a1adfa23d3da0964fa66eefbf83fc7f7a4020127f81b55ecd01e7457382
font_01_sfnt_off00011dd5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11DD5 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000135ec.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x135EC 11132 bytes
SHA-256: 10759ebfdb3952d91b219967da963011fa81feec06e5a56ea7446f616629cbbf