Malicious PDF — malware analysis report

Static analysis result for SHA-256 4ff91e2a312c8fb4…

MALICIOUS

PDF

81.1 KB Created: 2021-09-19 17:31:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 91ef8cfb922d20a696465e6df1641a40 SHA-1: b172af44a0ad08222085e62d018fbddb32727f9e SHA-256: 4ff91e2a312c8fb4fc36dac000d53f2ffb581f0c7610e5549c14393431359220
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, indicating a high likelihood of malicious intent. It contains numerous embedded URLs, many pointing to disposable domains, suggesting a link farm designed to redirect users. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' specifically flags this behavior. While no scripts were explicitly extracted, the PDF structure and embedded URLs are indicative of a phishing or malware distribution lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://crysiq.ru/uplcv?utm_term=how+to+downgrade+an+app+on+android PDF link annotation
    • http://rotarylaspalmas.org/documentos/file/97440376587.pdfIn PDF document text
    • http://nakloboucku.cz/uploaded/file/17935858837.pdfIn PDF document text
    • http://sergeybazarov.ru/file/9072238857.pdfIn PDF document text
    • http://postelezmasivu-brno.com/ckfinder/userfiles/files/relafodijutalopadabas.pdfIn PDF document text
    • http://businessdevelopmentcenter.pl/uploads/userfiles/files/dadadunufimaruloseso.pdfIn PDF document text
    • http://pastoret.it/userfiles/files/bizawiwigamujivupivewo.pdfIn PDF document text
    • https://doanandieuduong295doson.vn/namthuan/images/news/files/jalagopopuzuxepanope.pdfIn PDF document text
    • http://uts.edu.co/portal/app/ckfinder/userfiles/files/18821596967.pdfIn PDF document text
    • http://ilyxrace.com/userfiles/files/bulapuxejomekepapobexelej.pdfIn PDF document text
    • http://cngwalk.com/fckeditor/userfiles/image/ravedetogatogabogurebom.pdfIn PDF document text
    • http://bamboomfi.com/htdocs/cljr/data/files/vimesadowugavenimim.pdfIn PDF document text
    • http://orosweb.hu/ckfinder/userfiles/files/4165981114.pdfIn PDF document text
    • http://niszczeniewaw.pl/userfiles/file/29471964884.pdfIn PDF document text
    • https://morganmethod.tuesdaytrader.com/ci/userfiles/files/pinixipuxopudasetuliragoz.pdfIn PDF document text
    • http://werder-ritter.de/UserFiles/File/xojuwijixafowibo.pdfIn PDF document text
    • http://chochosanencino.com/uploads/files/80468329954.pdfIn PDF document text
    • http://jca-t.com/fck_image/file/11366379873.pdfIn PDF document text
    • https://jnvhardoi.org/ckfinder/userfiles/files/83728007908.pdfIn PDF document text
    • http://slkuang.com/v15/Upload/file/202199653308370.pdfIn PDF document text
    • http://moretonassets.net/userfiles/tinaxotemudenujapa.pdfIn PDF document text
    • http://getem.pl/files/file/63808733508.pdfIn PDF document text
    • http://tythb.com/uploadfile/files/gisenukewagebituwi.pdfIn PDF document text
    • http://mikllc.mn/uploads/files/xawowarilatavazupa.pdfIn PDF document text
    • http://kahsport.cz/userfiles/file/302624422.pdfIn PDF document text
    • http://emilygrilltogo.com/uploads/files/retekonenubenizudigu.pdfIn PDF document text
    • 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_off0000d906.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD906 17892 bytes
SHA-256: 44a57e061ed830207b3bba9967650f78eb6987d8702a726f1a79bcb91323359e
font_01_sfnt_off0001068b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1068B 10432 bytes
SHA-256: 2e225cae234a9a55b575ea54c87cdc0d3ee3f261601ef7794b927f6b7dda6bdb
font_02_sfnt_off00011e18.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11E18 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1