Malicious PDF — malware analysis report

Static analysis result for SHA-256 de799e23999ace39…

MALICIOUS

PDF

84.3 KB Created: 2021-09-09 12:25:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 80d2fb9cff8241ce3760b6a8c861d4d1 SHA-1: b408ef98b0d9b0adc589a2c73914482dc43c5128 SHA-256: de799e23999ace39949af8b888e7e4457954f29c0f69c2a20e3869d5dc90cdf6
126 Risk Score

Malware Insights

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

The PDF file was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, directing users to numerous external PDF files hosted on various domains. The presence of many distinct hosts and the use of UTM parameters suggest an attempt to obscure the true malicious intent and potentially track user engagement with phishing lures.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9972

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 http://www.casasemio.com.br/ckfinder/userfiles/files/49660316485.pdf
    • http://stagelight.pl/userfiles/files/vijisedatamakuto.pdf
    • https://xn--p3t29jo1ed4o4xw.tw/upload/files/25738111171.pdf
    • http://yalcinsezer.com/upload/ckfinder/files/dositog.pdf
    • http://poliinc.com/upload/files/21019045155.pdf
    • https://immsac.pe/sgi_userfiles/userfiles/files/34062351537.pdf
    • https://www.agencesramos.com/ckfinder/userfiles/files/73265441943.pdf
    • http://linpus.com/app/webroot/userfiles/files/zuropobazopazufexumowisam.pdf
    • http://www.skup.it/wp-content/plugins/formcraft/file-upload/server/content/files/1613937680ed85---66655540408.pdf
    • http://timnhanhonline.vn/upload/files/ramala.pdf
    • http://bisnismedsos.com/userfiles/file/belofozinemizedexopit.pdf
    • http://intelekt.biz/uploads/pages/files/74796418434.pdf
    • https://hoavily.com/uploads/files/11243710531.pdf
    • http://chinahk-ip.com/chinahk_ip/html/files/editor/file/dakujivovosodipun.pdf
    • https://myshalewell.com/userfiles/file/31914088104.pdf
    • http://zonweringbelgie.eu/ckfinder/userfiles/files/jezopuniwusedigokutepu.pdf
    • http://4bzsoftware.com/Images_upload/files/87366260335.pdf
    • http://kppzp.pl/userfiles/file/19651356840.pdf
    • https://openkomm.yussfone-crm.com/userfiles/file/nexadozovakoreloxilotitef.pdf
    • http://www.cerel.eu/images/wyswig_images/file/pupujatubixilep.pdf
    • https://noble-worldwide.com/wp-content/plugins/super-forms/uploads/php/files/6cdf11339e98bf04abf13357f0ec2414/62457378116.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/YTWXjIUwRh0/uplcv?utm_term=cheat+engine+android+connect+to+remote+system
    • 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_off0000dd31.bin
2b83d4250b564f1a9c42cfbfb452658506fbca73ae48668c8dca534fc9d2724b		 pdf-font-stream PDF embedded font (sfnt) at offset 0xDD31 10916 bytes
font_01_sfnt_off0000f624.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1		 pdf-font-stream PDF embedded font (sfnt) at offset 0xF624 16792 bytes
font_02_sfnt_off00010e36.bin
3c0f384b0de6ca1c623770704f214f27b2a38663af5a6a814b1b4c656190134e		 pdf-font-stream PDF embedded font (sfnt) at offset 0x10E36 20952 bytes

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