Malicious PDF — malware analysis report

Static analysis result for SHA-256 87fff224df82d5e8…

MALICIOUS

PDF

95.8 KB Created: 2021-09-12 05:50:49 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: c5887e764c0664d1ec5d311773b217c9 SHA-1: 39c3fb6c745d419148c870a311d9b51b4ddaec7e SHA-256: 87fff224df82d5e832513f700033cc4cfd3d9a4525bdb8d4bdc5d59859041c92
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. It contains a large number of embedded URLs, many of which point to disposable domains, suggesting a link farm designed to redirect users to malicious content. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic specifically indicates this behavior. While no scripts were directly extracted, the nature of the embedded links and the ML detection suggest an attempt to exploit vulnerabilities or deliver further malicious payloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9965

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 https://ksi-system.pl/editorfiles/file/89343160437.pdf In PDF document text
    • http://123podkrovie.sk/editor_uploads/files/87768801429.pdfIn PDF document text
    • http://shrlie.com/upload_fck/file/2021-9-4/20210904055721305619.pdfIn PDF document text
    • https://aptitudeclass.com/ckfinder/userfiles/files/13743986066.pdfIn PDF document text
    • https://www.disbel.es/ckfinder/userfiles/files/suxavito.pdfIn PDF document text
    • http://felixefontesadvogados.com.br/ckfinder/userfiles/files/temaxidukivesarides.pdfIn PDF document text
    • http://coiffurenais.com/userfiles/file/19024712899.pdfIn PDF document text
    • https://unosms.us/userfiles/file/30443731575.pdfIn PDF document text
    • http://sualpturizm.com/userfiles/file/32817270748.pdfIn PDF document text
    • https://inprovitcentroamerica.com/ckfinder/userfiles/files/91594905964.pdfIn PDF document text
    • https://www.aaptuk.org/ckfinder/userfiles/files/83170596436.pdfIn PDF document text
    • http://falconfam.com/ckfinder/userfiles/files/xezoritagubevezi.pdfIn PDF document text
    • https://khotelmarket.com/FileData/ckfinder/files/20210904_F5736518EE3F4E23.pdfIn PDF document text
    • https://pfgmm.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/16139ea05d53e2---wibilade.pdfIn PDF document text
    • http://xn--z92bzy85x.com/userData/board/file/mogazawizumijusiweliroz.pdfIn PDF document text
    • http://zgkimsteszew.pl/img/upload/files/85225627294.pdfIn PDF document text
    • http://abwingsde.com/uploads/files/9205688542.pdfIn PDF document text
    • http://dogomanhnghia.com/uploads/files/ragasomizekokusim.pdfIn PDF document text
    • http://xn--9w3b11kh5l.com/ckupload/files/66006991713.pdfIn PDF document text
    • http://obasekiestates.com/UserFiles/file/denutotejomi.pdfIn PDF document text
    • http://savages.lu/imagesRTE/files/42136608289.pdfIn PDF document text
    • http://syuncyoku.jp/upload/file/99936353325.pdfIn PDF document text
    • http://geomanteia.com/userfiles/files/78306716253.pdfIn PDF document text
    • http://psychanalyste-gard.fr/ckfinder/userfiles/files/maluk.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/GLLx1DTH0VQ/uplcv?utm_term=katamail+su+androidPDF link annotation
    • 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_off000115a6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x115A6 17400 bytes
SHA-256: 7820bb265ef178d3fbd50af0f175c8230aec08fdb5911252463157c3dab9a15c
font_01_sfnt_off000141f3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x141F3 10368 bytes
SHA-256: ead2d1442a03ab6a49e62f1efe022fc436650860c8cf19ce77405ad198b4f055
font_02_sfnt_off0001594a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1594A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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