Malicious PDF — malware analysis report

Static analysis result for SHA-256 ef97ba9e5cf155a2…

MALICIOUS

PDF

83.1 KB Created: 2021-09-13 12:21:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: ab199f4ccab65b84276fbf0a171e4ee4 SHA-1: 7b63b6c5734aa0f2d6e6283daa4654944ee7436e SHA-256: ef97ba9e5cf155a22133b252c0e4bce4398e9bf95c9506e1d820e7b1286052a7
196 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 links to external websites, many of which are hosted on compromised CMS uploads or disposable domains, suggesting a link farm or phishing lure. The presence of PDF_RANDOM_URL_LINK and PDF_SEO_DISPOSABLE_LINK_FARM heuristics indicates a pattern of directing users to potentially malicious or compromised sites. While no scripts were explicitly extracted, the nature of the URLs and the PDF structure strongly suggest an attempt to redirect users for malicious purposes.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9955

Heuristics 7

  • 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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://unipell.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1613d91cd68dc5---wirevafak.pdf In PDF document text
    • https://confidence-ist.mktechsol.com/ckfinder/userfiles/files/taledobikapuwuxalulule.pdfIn PDF document text
    • https://by-express.com/upfiles/editor/files/banonosujalukabemivudevem.pdfIn PDF document text
    • https://eklyps.net/images/file/30597067124.pdfIn PDF document text
    • http://abwferrellpkwy.com/uploads/files/fimilagunedodegebareve.pdfIn PDF document text
    • https://iohrp.org/f_files/files/duvurudulapolofi.pdfIn PDF document text
    • http://clinton.abwingsmd.com/uploads/files/59352971971.pdfIn PDF document text
    • http://veterinarioassociatopacinidallatorre.eu/userfiles/files/vemomarukakaxuzudozeleje.pdfIn PDF document text
    • http://viral-list-machine.com/ckfinder/userfiles/publics/files/89916643516.pdfIn PDF document text
    • http://in-dapt.com/wp-content/plugins/formcraft/file-upload/server/content/files/16139315639db0---7042050431.pdfIn PDF document text
    • http://globomax.eu/userfiles/file/tenivulanezefom.pdfIn PDF document text
    • https://at2-turbo-j3t.com/contents/files/95190096173.pdfIn PDF document text
    • https://vcvscr.cz/www/www/fckphotos/file/21946684127.pdfIn PDF document text
    • http://hk-keber.de/images/file/9628441065.pdfIn PDF document text
    • http://americasbestmanassas.com/uploads/files/92721151521.pdfIn PDF document text
    • https://digitaluzaktanegitim.com/calisma2/files/uploads/41615898700.pdfIn PDF document text
    • https://laetitiabernard.fr/images/file/59714119558.pdfIn PDF document text
    • https://praktijk-fix.nl/userfiles/image/file/relipumukaxumu.pdfIn PDF document text
    • https://theelementrama9.com/userfiles/files/purezisadafuxovor.pdfIn PDF document text
    • http://plusbateria.com/wp-content/plugins/formcraft/file-upload/server/content/files/161381e479e529---28248244239.pdfIn PDF document text
    • https://farmacieitaliane.com/documenti/file/6496915182.pdfIn PDF document text
    • http://multiseal.com.ph/wp-content/plugins/formcraft/file-upload/server/content/files/1612e98a6d5cc8---pinoboluvuvivenawaf.pdfIn PDF document text
    • http://onlinetalk.jp/app/webroot/img/fckfiles/file/pexugolejeginok.pdfIn PDF document text
    • http://bright-inter.com/file_media/file_image/file/24564442045.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3CAf4wW3hvY/uplcv?utm_term=spectroscopy+of+organic+compounds+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_off0000db5b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDB5B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f36d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF36D 18828 bytes
SHA-256: 51c755492a78523c84b280cd34e2e00f591779d960ade3e7c12e47e38a516d2d
font_02_sfnt_off000124e8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x124E8 11204 bytes
SHA-256: d466c508584394e5a49908575f5f76cbd28e8ef36ffffb5b029c014f9bb95235