Malicious PDF — malware analysis report

Static analysis result for SHA-256 4b5910c5b2ca9fb5…

MALICIOUS

PDF

87.1 KB Created: 2021-09-17 06:48:43 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-20
MD5: 1311632f67ee82980bfbcfbb504f8bd5 SHA-1: 027c8fe5b7ca88f9606b60e0086313a38846f63b SHA-256: 4b5910c5b2ca9fb57f4e6e9a4e970bd92ab7330f6f0b8e50cbaaaf9f96153434
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs that point to other PDF files hosted on various domains, many of which appear to be compromised CMS upload directories. The ML classifier and ClamAV detection strongly indicate malicious intent, likely related to phishing or malware distribution. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' suggests this is part of a link farm, possibly for SEO manipulation or to obscure the true destination of malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9976

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://minhgianggroup.vn/upload/files/dewevolitotus.pdf In PDF document text
    • http://jmyhship.com/uploadfile/files/72155831601.pdfIn PDF document text
    • http://remobudostol.pl/pliki/manoxizefupipar.pdfIn PDF document text
    • http://thevale.us/userimages/pebopanu.pdfIn PDF document text
    • http://www.s4b.nl/upload/files/boxutixidoru.pdfIn PDF document text
    • https://copacndg.com/images/uploads/files/pusetaj.pdfIn PDF document text
    • http://kirsanov-maslo.ru/uploads/28558336219.pdfIn PDF document text
    • http://solmoda.it/userfiles/files/famizikexaleko.pdfIn PDF document text
    • https://dodatkireklamowe.pl/web/uploads/files/94820459004.pdfIn PDF document text
    • https://stcatherine.ac.ug/wp-content/plugins/formcraft/file-upload/server/content/files/1613cefac1cbf4---16872965338.pdfIn PDF document text
    • http://thucancakoihikari.com/luutru/files/96674689160.pdfIn PDF document text
    • https://dom4m.lv/userfiles/files/wosezeron.pdfIn PDF document text
    • http://laureysnv.be/uploads/files/podevezerefalekubum.pdfIn PDF document text
    • http://offerseir.com/basefile/offerseircom/files/90879217441.pdfIn PDF document text
    • http://giasudaihocsupham.com/Images_upload/files/8046543955.pdfIn PDF document text
    • http://daedukgs.com/admin/fckeditor/data/file/20210913223013.pdfIn PDF document text
    • http://recruiters-zone.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612eada898392---mizuwanav.pdfIn PDF document text
    • https://thebottombillion.org/business_school/uploads/file/xiforu.pdfIn PDF document text
    • https://amartzon.store/wp-content/plugins/super-forms/uploads/php/files/c6d25b76a0bba27a8ee91004d9669ddb/5901031005.pdfIn PDF document text
    • http://aldo-ins.com/userfiles/file/gogiguwazetu.pdfIn PDF document text
    • https://reviewz.eu/app/webroot/files/userfiles/files/gasujufipipugof.pdfIn PDF document text
    • http://netichikawaya.com/userfiles/file/xerunazase.pdfIn PDF document text
    • http://kengosushionlineorder.com/uploads/files/93520794709.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/1xuhb7AK25c/uplcv?utm_term=hatsune+miku+v4PDF 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_off0000ec8a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEC8A 10332 bytes
SHA-256: c2af1a3680f883228457241cf3972759dd2f529e6d5fdb5fbb5d50cb4946ac48
font_01_sfnt_off000103d5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x103D5 19516 bytes
SHA-256: 4b2754e2dce60cef02351c6ee73e5b24890a4f3a9c701dc0d554c3bee2dcb955
font_02_sfnt_off000136cf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x136CF 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1