Malicious PDF — malware analysis report

Static analysis result for SHA-256 c8cdb8508df6eeb7…

MALICIOUS

PDF

71.7 KB Created: 2021-09-14 01:03:29 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 5ed2142636bf1431f2ceb33864020e85 SHA-1: 2a4cb8553e64a9b2fc23a130bcbaedf28a1e821e SHA-256: c8cdb8508df6eeb74f5e1d3734cac44ff0bcd56fb1146131da1dcd6d49b962b3
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as a malicious PDF by ClamAV and an ML classifier. It contains numerous embedded URLs, many pointing to PDFs hosted on various domains, suggesting a link farm designed to redirect users. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic further supports this, indicating a tactic to obscure the true destination. While no scripts were explicitly extracted, the nature of the embedded URLs and the link farm heuristic strongly suggest a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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 https://highfieldhousehotel.net/nbloom/fckuploads/file/vaziwukokuvuxobitolivem.pdf In PDF document text
    • http://scuderieverdina.it/scuderia/userfiles/file/23814290345.pdfIn PDF document text
    • http://usefchina.com/uploadfile/file///2021090604305658.pdfIn PDF document text
    • http://provia-events.de/pics/fotos/1/file/tadatezisetefino.pdfIn PDF document text
    • https://dmddsgn.com/wp-content/plugins/super-forms/uploads/php/files/d5695e88a020c352dc6a372391267ef6/12026193200.pdfIn PDF document text
    • https://aayams.com/userfiles/file/67107094998.pdfIn PDF document text
    • http://111-orte.com/testarea/cwsCMSlight/media/files/wuparorunaluwexabemefejir.pdfIn PDF document text
    • https://thieumaunao.vn/workspace/develop/uploads/ck_upload/files/59958776542.pdfIn PDF document text
    • http://hasdeu.md/data/userfiles/files/jaligegi.pdfIn PDF document text
    • https://greenfuturevietnam.com/Upload/files/79262442875.pdfIn PDF document text
    • http://ketnoikienthuc.com/upload/files/37418304158.pdfIn PDF document text
    • https://dellrein.ru/content/file/28381715173.pdfIn PDF document text
    • http://2girlstrippin.com/wp-content/plugins/formcraft/file-upload/server/content/files/16133accc68218---jolulujigunubibuxasasof.pdfIn PDF document text
    • http://teaterskolen-efteruddannelsen.dk/ckfinder/userfiles/files/jowoviwupapotuludimebe.pdfIn PDF document text
    • https://adikkedua.com/contents/files/sezuxivisokoloxopivuj.pdfIn PDF document text
    • http://acrclubinversores.com/files/galeria/files/81465111960.pdfIn PDF document text
    • http://klwas.org/userfiles/images/file/18206183206.pdfIn PDF document text
    • http://valkexclusief.reviews/app/webroot/files/userfiles/files/lufetag.pdfIn PDF document text
    • https://www.emcp-pmce.ca/_includes/ckfinder/userfiles/files/63149720061.pdfIn PDF document text
    • https://mosconi.net/userfiles/file/67082547871.pdfIn PDF document text
    • https://s-oil.hoakhanh.vn/uploads/image/files/dusuloxesuv.pdfIn PDF document text
    • http://fitviewer.biz/files/file/bozatifegor.pdfIn PDF document text
    • http://gesundezellen.com/neu/userfiles/file/xipite.pdfIn PDF document text
    • http://ventmetal.ru/userfiles/files/foxonowevoxenazewavumixu.pdfIn PDF document text
    • http://zhouzhuanx.com/v15/Upload/file/202191455475082.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/ngfLrbzwjls/uplcv?utm_term=system+application+software+examplesPDF 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_off0000b719.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB719 15444 bytes
SHA-256: 1661277cee0bd7702bb18ca2f5a3c3da9c510a0bd22e4fcb42a5844acb1b2969
font_01_sfnt_off0000dee0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDEE0 11016 bytes
SHA-256: 2b2d61a5b377c4be39b10beab3ea8b94039ca6632faa81ed4ff1e35ffebf285d
font_02_sfnt_off0000f88b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF88B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1