Malicious PDF — malware analysis report

Static analysis result for SHA-256 c77083fd87e295f7…

MALICIOUS

PDF

69.5 KB Created: 2021-09-28 10:13:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 23a6d689a0694d199a29e1e00afa492b SHA-1: 9cb2e5e25a4b6d37bd6eb1d23b49616269c9494a SHA-256: c77083fd87e295f750a7db7b2461212b37a8976317c244628424bba77eee717a
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file flagged by ClamAV and an ML classifier as malicious. It contains numerous embedded URLs, many of which point to PDF files hosted on distinct domains, indicating a link farm. The presence of 'utm_term=app+store+mod+apk+ios' in one URL suggests a potential lure related to app stores or modified applications. While no scripts were explicitly extracted, the PDF structure and the nature of the URLs strongly suggest it's designed to redirect users to malicious websites for further exploitation or phishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9849

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://bokaichenyu.com/upload/files/55132857862.pdf
    • http://ekbdrive.ru/ckfinder/userfiles/files/33992506155.pdf
    • https://aimtronu.org/userfiles/file/bokemoto.pdf
    • https://netlandschool.cl/files/96326768948.pdf
    • http://currycornersugarland.com/admin/images/file/zosogomutijovovaka.pdf
    • http://poongdung.com/FileData/ckfinder/files/20210909_42175328F4485361.pdf
    • http://yourtruck.be/upload/ckeditor/file/tifileperoxavedebijolos.pdf
    • http://pass38.com/images/contentimages/files/ronatubisara.pdf
    • http://pospatrans.cz/UserFiles/File/mezukag.pdf
    • https://riminabda.sk/userfiles/file/7296903811.pdf
    • http://medicapoland.pl/uploaded/file/nabego.pdf
    • http://www.gamylai.vn/uploads/files/guramuzofuki.pdf
    • http://kozelsk-adm.ru/files/uploads/files/winam.pdf
    • http://az4group.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/161424d9758238---32814383430.pdf
    • http://f-kcc.jp/user_data/userfiles/files/52866826656.pdf
    • http://119pump.net/d/files/42927190084.pdf
    • https://coachtourbusrental.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613c42502c9d7---losawedibebajo.pdf
    • http://philipp-haberland.de/images/upload/file/rolupokeramaxifilepapomu.pdf
    • https://espiber.cl/images/uploadedimages/file/subikukovofixopewoxodijar.pdf
    • http://fnathservices.com/upload/file/14683283184.pdf
    • http://donleroy.net/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/4943188429.pdf
    • http://synerfreight.com/syner_upload/images/files/mupavanivilabifanelewag.pdf
    • http://manhtreminhduc.com/webroot/img/files/72292127951.pdf
    • http://falegnameriacastiglione.it/userfiles/files/66345071277.pdf
    • http://creationart.hu/files/file/89016348215.pdf
    • http://aumnat2car.com/ckfinder/core/connector/php/upload/files/meravubak.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/LPIa9PGmDLg/uplcv?utm_term=app+store+mod+apk+ios
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000b053.bin
c8f20fc3cc78e393b0dcb0a68c56455b3447cf9182711e45bb7a8fa7b46f6607		 pdf-font-stream PDF embedded font (sfnt) at offset 0xB053 10476 bytes
font_01_sfnt_off0000c835.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1		 pdf-font-stream PDF embedded font (sfnt) at offset 0xC835 16792 bytes
font_02_sfnt_off0000e047.bin
b35f7b1a5196c05f662678f026a867a7356ddb29e6fcf2d9b0aa4e1c89911596		 pdf-font-stream PDF embedded font (sfnt) at offset 0xE047 15500 bytes

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