Malicious PDF — malware analysis report

Static analysis result for SHA-256 66994a5eb86712d7…

MALICIOUS

PDF

83.3 KB Created: 2021-09-19 01:02:17 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 35bfba74a03719ebec7c1af2e38331b6 SHA-1: ae6cc70b77030aa74eafa9d70ad1d4cdefe74152 SHA-256: 66994a5eb86712d7fda7b5cbc7d6887d1a8279cf6c52e5b82ec428fa9be5a724
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The sample is a PDF file flagged by multiple heuristics and a machine learning classifier as malicious. It contains numerous embedded URLs pointing to PDFs hosted on disposable domains, indicating a link farm designed to obscure the true malicious destination. The ClamAV detection as 'Pdf.Phishing.Trojan' further supports a phishing or trojan distribution intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://runhouchem.com/upload/files/rirojubozugukagav.pdf
    • http://zetrade.cz/userfiles/file/15113696796.pdf
    • http://ativn.com/upload/file/garidajederux.pdf
    • http://panhongbo.com/ckfinder/userfiles/site_eachfun_com/files/31249022551.pdf
    • http://wirheiraten.de/images/file/65079847787.pdf
    • http://bukhatirhomes.com/userfiles/file/73991197667.pdf
    • http://coachhouse.info/assets/file/posagupokel.pdf
    • http://fantacyhandicraft.com/userfiles/file/59245833442.pdf
    • http://kantoromega.pl/userfiles/file/43104799075.pdf
    • http://jcon-aps.dk/userfiles/file/43537635779.pdf
    • http://youil.org/userData/board/file/16038945152.pdf
    • https://retrofitoman.com/ckfinder/userfiles/files/48675930746.pdf
    • https://ehotelgateway.com/bot/ckfinder/uf/files/lubabovunekuxipemasupom.pdf
    • https://rmissio.pl/wp-content/plugins/formcraft/file-upload/server/content/files/1613362617507c---17395543110.pdf
    • http://maekuangudomthara.com/ckfinder/userfiles/files/24564333106.pdf
    • https://empresa-venta.hr/files/4701864038.pdf
    • http://2222.netsociality.com/upload/files/rufesujotefalabodufo.pdf
    • https://vinatech.com/userfiles/file/morunidajibirimirexovur.pdf
    • http://andreagarciam.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614659835c9b1---17928379626.pdf
    • https://erdenetpost.mn/userfiles/files/tomad.pdf
    • https://testgit.begurholidays.com/uploads/userfiles/files/wunenaxizesex.pdf
    • http://kaztelcom.kz/ckfinder/userfiles/files/nutojajedokite.pdf
    • http://ljjxmining.com/uploadfile/file///2021091905591232.pdf
    • https://www.naabelectric.com/userfiles/files/54860165688.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/3vuEKuznOb8/uplcv?utm_term=android+5.1+update
    • 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_off0000df71.bin
4efebe9e12c192d99ea1e3d34dcf8182bd7a934a81a3c15e4646882a37c52ba9		 pdf-font-stream PDF embedded font (sfnt) at offset 0xDF71 10504 bytes
font_01_sfnt_off0000f789.bin
cbd90cc4f582d8955d1e52ba6679a1d7f94073ca203fcb84f3cb29a7e744abdd		 pdf-font-stream PDF embedded font (sfnt) at offset 0xF789 18580 bytes
font_02_sfnt_off000127c2.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1		 pdf-font-stream PDF embedded font (sfnt) at offset 0x127C2 16792 bytes

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