Malicious PDF — malware analysis report

Static analysis result for SHA-256 2131c21d56fee7f5…

MALICIOUS

PDF

85.2 KB Created: 2021-10-23 00:30:54 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 87fefa7a40d5e53c3e5ed9ffde762e4b SHA-1: 7e4aa84404c6bd767e17855d606d26812863dd13 SHA-256: 2131c21d56fee7f5baeef4b27145bac6d2c396c759cb7e93277e4ec363233170
156 Risk Score

Malware Insights

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

The file was identified as malicious by ClamAV and an ML classifier, with heuristics indicating it functions as a link farm. Multiple URLs extracted from the document point to disposable hosting or compromised CMS upload storage, suggesting an attempt to lure users to external sites. No scripts were extracted, and the document body was unreadable, limiting further analysis of specific payloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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 http://analogsys.com/uploaded/file/326293582615dcfcf2bf4a.pdf In PDF document text
    • https://cosmopolitanhotel.lastrada.bg/uploads/wysiwyg/files/vezosesuwigesixi.pdfIn PDF document text
    • http://skipjackpoke.com/ckfinder/userfiles/files/zipafesogevinavija.pdfIn PDF document text
    • http://alrehabourhome.com/userfiles/files/sejedituvadeguvuj.pdfIn PDF document text
    • https://www.golaw.net/wp-content/plugins/formcraft/file-upload/server/content/files/1614b66b8ce34a---xuwalifugabaf.pdfIn PDF document text
    • https://polenhosting.com/calisma2/files/uploads/28703257739.pdfIn PDF document text
    • http://vinag7furniture.com/app/webroot/files/editor_upload/files/wiropasu.pdfIn PDF document text
    • http://studiogeologicotrilobite.com/userfiles/files/gamoluzovelojunupapurini.pdfIn PDF document text
    • https://plentis.eu/ckfinder/userfiles/files/laradipaz.pdfIn PDF document text
    • https://medgal.pl/admin/ckfinder/userfiles/files/1993140675.pdfIn PDF document text
    • http://didongsinhvien.com/upload/files/niwujirexotalinuviwixise.pdfIn PDF document text
    • https://swimproject.eu/wp-content/plugins/super-forms/uploads/php/files/a327f6a5e9e7bf7e6d74fcede35cb7aa/vigudawapemetifa.pdfIn PDF document text
    • https://sukienmiennam.com/userupload/files/fosokoxalegoju.pdfIn PDF document text
    • https://tour-paris-guide.com/cite_imgs/file/10851689242.pdfIn PDF document text
    • https://www.hotel-palladium.gr/wp-content/plugins/super-forms/uploads/php/files/anuapf1ssqaabdrld02smtjhd3/71824371415.pdfIn PDF document text
    • http://gwynnoak.abwingsmd.com/uploads/files/78088758610.pdfIn PDF document text
    • https://terminal.hr/userfiles/file/sosakawofovusiwaremibarid.pdfIn PDF document text
    • https://www.enviedecrire.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614c6444f0597---zusadaw.pdfIn PDF document text
    • https://gestionarival.com/userfiles/file/1901353009.pdfIn PDF document text
    • http://vkp.ru/upload/global/file/sobepafosutadapo.pdfIn PDF document text
    • https://dnm.tw/uploads/files/202109080935339778.pdfIn PDF document text
    • http://artpolyclinic.com/file/files/20501735926.pdfIn PDF document text
    • http://feedproxy.google.com/~r/Xvkpad/~3/RC0zOYPQW8A/uplcv?utm_term=more+and+more+crossword+cluePDF 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_off0000e8ac.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE8AC 10520 bytes
SHA-256: 6225d9ce39169e09ac83665a51ff12652a1cfe51687d2c6ec7ea429c77f33e4f
font_01_sfnt_off000100a8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x100A8 17788 bytes
SHA-256: aed7deae15e51114737b01d6cd3cce2a06cd890ec345b1d06321e0096b20af86
font_02_sfnt_off00012ed7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12ED7 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1