Malicious PDF — malware analysis report

Static analysis result for SHA-256 da21b3d8e2c2d6a2…

MALICIOUS

PDF

82.6 KB Created: 2021-09-19 02:21:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: e2d2dd7d73783d14cc21abd087a5aff4 SHA-1: b4675bdde65154699884e9d73a4db0caf9b84e0b SHA-256: da21b3d8e2c2d6a21316c72c74fee81a460139d44e6453e5e7b3b7b55d318d1d
126 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, directing users to multiple external URLs, one of which is hosted on disposable infrastructure. The document body is heavily obfuscated and appears to contain metadata from the wkhtmltopdf tool, suggesting it was generated programmatically rather than being a user-authored document.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9985

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://weiken-rc.com/upload/files/1318637255.pdf In PDF document text
    • http://andreevka.topmebli.com/content/xuploadimages/file/zadusimovapa.pdfIn PDF document text
    • http://lmnn.ru/userfiles/file/32004282430.pdfIn PDF document text
    • http://worksafeorg.com/wp-content/plugins/super-forms/uploads/php/files/bd1c8ofhgbs6528eksm5saiq64/mivinar.pdfIn PDF document text
    • http://timavoshipsupply.it/userfiles/file/45278684518.pdfIn PDF document text
    • http://kindergartenhelden.at/upload/file/73014974028.pdfIn PDF document text
    • http://metabolitplus.ru/files/file/fakudadufumusegegewuv.pdfIn PDF document text
    • https://posaonakosovu.com/ckfinder/userfiles/files/lowimagugulonitaxebopi.pdfIn PDF document text
    • http://putzlappenborner.at/editor_up/vepafabexokivoz.pdfIn PDF document text
    • https://lajovisena.com/gallery/file/vijekasizixoributegexaf.pdfIn PDF document text
    • http://biomax.shop/filespath/files/20210919063828.pdfIn PDF document text
    • https://marljivo.hr/UserFiles/files/40079466961.pdfIn PDF document text
    • http://klusjesindex.nl/images/uploads/vanaxavudovenogid.pdfIn PDF document text
    • http://gmicropilotes.com/uploads/files/81928957158.pdfIn PDF document text
    • http://www.civilhospitalpalampur.in/img/uploads/files/21958629252.pdfIn PDF document text
    • https://foodvellythailand.com/upload/files/ketoverufeder.pdfIn PDF document text
    • https://rts-wm.com/ckfinder/userfiles/files/rejigimizememewazamed.pdfIn PDF document text
    • https://kaparatt.com/images/File/22783393030.pdfIn PDF document text
    • http://hndgyl.com/v15/Upload/file/2021971152149215.pdfIn PDF document text
    • http://drumlockingclamp.com/FCK_Editor_Images/files/zupuru.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/PmAiG5ZyT-k/uplcv?utm_term=things+to+put+in+a+house+in+minecraftPDF link annotation
    • https://tes-sys.com/uploads/ckfinder/files/20210906/16308823978794.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_off0000dd7a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD7A 10944 bytes
SHA-256: a9db863878b6e5c537dd9376e099f30452993d41cc832d94d84b1bb6fa54147a
font_01_sfnt_off0000f6b0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF6B0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010ec2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10EC2 17960 bytes
SHA-256: 7d5d010270e23ff59873a4cd46ca8331c9df4d4ed5e35b411a10dc8dd3a40db7

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