Malicious PDF — malware analysis report

Static analysis result for SHA-256 5510bece7e5f1e48…

MALICIOUS

PDF

68.2 KB Created: 2021-09-17 09:44:13 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 20a2dab1d299dcd3e3f31cef4489f41c SHA-1: d800b237af46e36c26860ed976a6f9b5a7e08d60 SHA-256: 5510bece7e5f1e48aa719e94f7b33dc7d79119c4bc17b10d76cf698f33da1992
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The PDF file contains a large number of links to other PDF documents hosted on various domains, many of which appear to be compromised upload directories. The ML classifier strongly indicated maliciousness, and the link farm structure suggests a distribution mechanism for further malware or phishing content. No scripts were extracted, limiting the analysis of direct execution capabilities.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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://brukspec.pl/upload/file/75983363650.pdf In PDF document text
    • http://fine-cottage.ru/userfiles/files/wixufabilofeviloxutawezi.pdfIn PDF document text
    • http://cathyknightwaite.com/ckfinder/userfiles/files/sadivuvujelozosamuzi.pdfIn PDF document text
    • http://flex-link.cn/uploadfiles/files/fafanefuvomajagogomifapud.pdfIn PDF document text
    • https://cubic.is/userfiles/file/83496984673.pdfIn PDF document text
    • http://www.cuerpomenteyespiritu.es/wp-content/plugins/formcraft/file-upload/server/content/files/16143cf93a083b---jupasexuranera.pdfIn PDF document text
    • http://entryexpress.online/chapter_images/files/koxinemore.pdfIn PDF document text
    • http://dmkert.hu/files/file/88342013891.pdfIn PDF document text
    • https://frennphotography.com/wp-content/plugins/formcraft/file-upload/server/content/files/16140cf0d52755---laxesofamofafesofitizibeg.pdfIn PDF document text
    • http://dainindo.com/Uploads/userfiles/files/89777324646.pdfIn PDF document text
    • http://wumag.pl/userfiles/file/rajapoxemovamajigimim.pdfIn PDF document text
    • https://konchris.com/userfiles/file/1630956223.pdfIn PDF document text
    • http://como.gattinonimondodivacanze.it/themes/userfiles/files/24815056524.pdfIn PDF document text
    • http://forma8.kz/ckfinder/userfiles/files/37649501479.pdfIn PDF document text
    • https://bibliothequedesarts.ch/ckfinder/userfiles/files/14130392849.pdfIn PDF document text
    • http://sgyscom.com/upload_fck/file/2021-9-14/20210914141419926086.pdfIn PDF document text
    • http://andreaslasnik.com/data/files/fomokebetuvidinu.pdfIn PDF document text
    • https://elpollopaulino.com/cenavarra_userfiles/files/54015321900.pdfIn PDF document text
    • http://shopcloud.cloud/ckfinder/userfiles/files/lijapalozamonopapimas.pdfIn PDF document text
    • http://casaatlantida.com/userfiles/file///77111207804.pdfIn PDF document text
    • https://matharu.ae/userfiles/file/lajevavofi.pdfIn PDF document text
    • http://steinemann-ag.ru/wuxexakas.pdfIn PDF document text
    • http://www.hypnotiseur.com/wp-content/plugins/formcraft/file-upload/server/content/files/16133d53897191---63504065499.pdfIn PDF document text
    • http://scard.vn/app/webroot/uploads/files/jexewixanizijavidepuj.pdfIn PDF document text
    • http://eviljoy.com/UserFiles/File/95528833118.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/1xuhb7AK25c/uplcv?utm_term=d%26d+3.5+eberron+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_off0000b3ff.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB3FF 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000cc11.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCC11 14912 bytes
SHA-256: fe675d26644e427dd24ca14fde3a52c1bd91d5ec72ae3cb96a14385345079b60
font_02_sfnt_off0000f0b3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF0B3 9076 bytes
SHA-256: f695977626623e59fedb2fbedebd468d0acf89ff6f6ceafeb3cee4351ddee6c8