Malicious PDF — malware analysis report

Static analysis result for SHA-256 16c5a2f182cb9efc…

MALICIOUS

PDF

74.5 KB Created: 2021-09-28 04:20:21 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: cb1f8b7915bf3134be1f7491607ff288 SHA-1: 4a49c46ebcaab03a6d899f54caf7808423a252fe SHA-256: 16c5a2f182cb9efc226b39e8d78303926304a732bbc7de18b44f7c65c309ec73
126 Risk Score

Malware Insights

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

The sample was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. The PDF contains numerous embedded URLs, many of which point to disposable domains and are structured as a link farm, suggesting a tactic to manipulate search engine results or distribute further malicious content. The presence of external URIs and the link farm heuristic strongly suggest the PDF's primary purpose is to redirect users to potentially harmful sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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.
  • 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 http://goldsunjsc.com/upload/files/zekodekowevurezeposikek.pdf In PDF document text
    • http://zvaracskaskola.eu/editor_uploads/system/files/29460403037.pdfIn PDF document text
    • http://elateridae.com/images/FCKeditor/file/nowiremofazibitujarufoli.pdfIn PDF document text
    • http://www.macrolepidoptera.hu/userfiles/files/2772622492.pdfIn PDF document text
    • http://rigassprotes.lv/uploadz/file/38416445756.pdfIn PDF document text
    • http://gpszone.hu/upload/userfiles/file/62373923938.pdfIn PDF document text
    • http://fijiembajak.com/uploads/ck_uploads/files/3651067912.pdfIn PDF document text
    • http://dxqzx.com/ckfinder/userfiles/files/20210926_030037.pdfIn PDF document text
    • https://indiantalentjunction.com/milan/media/68861237595.pdfIn PDF document text
    • https://dalycity.com/wysiwygfiles/file/21908331393.pdfIn PDF document text
    • http://attep.com/home/sandbox/domains/heekee.com.hk/public_html/ckfinder/userfiles/files/ketibokakubabiraduwufewa.pdfIn PDF document text
    • http://easyliveconstruction.com/ci/userfiles/files/83237635645.pdfIn PDF document text
    • http://autoset66.ru/admin/ckfinder/userfiles/files/55192199549.pdfIn PDF document text
    • http://alvasari.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613635da75e5c---nemogugi.pdfIn PDF document text
    • https://etre-cheval.fr/Applications/MAMP/htdocs/etre%20cheval/news_pix/file/29108711151.pdfIn PDF document text
    • http://ceomit.com/fckupload/file/giziregakeraronisanuvodi.pdfIn PDF document text
    • https://ruxthai.com/ckfinder/userfiles/files/87027515578.pdfIn PDF document text
    • http://engroupe.ca/aym_image/files/dolag.pdfIn PDF document text
    • https://aromamarketing.md/img/files/takudazuzegedumevuriwelaz.pdfIn PDF document text
    • https://rrr71.ru/upload_picture/4091121690.pdfIn PDF document text
    • http://manchetenewsms.com.br/ckfinder/userfiles/files/49332507073.pdfIn PDF document text
    • https://accesoriosalmayor.com/images/userfiles/file/xugebedexupejipotiliruve.pdfIn PDF document text
    • https://www.sudicobank.com/ckfinder/userfiles/files/79214401597.pdfIn PDF document text
    • https://combrooncom.com/contents/files/pezoruguwizukuvalanimul.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/BkSY9tpko7c/uplcv?utm_term=kundalini+yoga+books+in+telugu+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_off0000b98a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB98A 18948 bytes
SHA-256: 29c2b36c2df80f893895c71048d068d28dcf15f566fd6cb08537a4eecd154413
font_01_sfnt_off0000ead3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEAD3 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000102ea.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x102EA 11008 bytes
SHA-256: ae5d3b62bd3a920f5ecfabfce83c0564cabdd046c296c883e047f33d2f9a4e1c