Malicious PDF — malware analysis report

Static analysis result for SHA-256 338d3835c62bfd69…

MALICIOUS

PDF

72.2 KB Created: 2021-09-27 21:44:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: 279a96c3f94b8e1510d826c43a284ece SHA-1: 76a9897713efdecaeea8b8477dff875a49343db5 SHA-256: 338d3835c62bfd69d2a8cd4d0c294bbdae82c83611296e0dc4d34562470b1248
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file flagged by ML classifiers and ClamAV as malicious. It contains numerous embedded URLs pointing to various PDF files hosted on different domains, suggesting a link farm or content distribution network. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic indicates a pattern of using disposable hosting for a large number of distinct links, which is often associated with SEO manipulation or malware distribution. While no scripts were explicitly extracted, the nature of the embedded URLs and the heuristics suggest an intent to redirect users to potentially harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9940

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://nsck-cykelmotion.dk/ckfinder/userfiles/files/dukaxugog.pdf In PDF document text
    • https://lodoshosting.com/calisma2/files/uploads/75876933761.pdfIn PDF document text
    • https://alcoquimicos.com/ckfinder/userfiles/files/voradakomefijuzapirinam.pdfIn PDF document text
    • http://zezoalza.com/ckupload/files/42469044697.pdfIn PDF document text
    • http://mylodge-naoshima.com/images/blog/file/lifovimusog.pdfIn PDF document text
    • http://xn----otbb6ahq3d.xn--p1ai/ckfinder/userfiles/files/29774499960.pdfIn PDF document text
    • http://unityproductions.com/upload/files/94210848145.pdfIn PDF document text
    • http://elcivan.com/admin/UserFiles/file/ludabufiluwigosudub.pdfIn PDF document text
    • http://xn--82cac8d3ajrc0gd0bo4a7nf3qg.com/userfiles/files/4620564098.pdfIn PDF document text
    • https://nusamulticentralestari.com/Uploads/userfiles/files/bikininilejagesavamib.pdfIn PDF document text
    • http://www.tobywells.org/media/fckdir/file/mifozawuzixufutaronona.pdfIn PDF document text
    • http://aranykoronakft.hu/userfiles/file/9283030295.pdfIn PDF document text
    • http://zlzljc.com/uploadfile/file///2021091005525268.pdfIn PDF document text
    • http://uzmansporzeminkaplama.com/resimler/files/28864291446.pdfIn PDF document text
    • https://netlandschool.cl/files/89197492102.pdfIn PDF document text
    • https://honghow.com/ckfinder/userfiles/files/66605005560.pdfIn PDF document text
    • http://www.mattig-accounting.bg/fisiere/file/84868084511.pdfIn PDF document text
    • https://valstybestarnyba.com/upckfinder/files/gamutus.pdfIn PDF document text
    • https://escritacontabilidade.net/fotos/news/file/32943601168.pdfIn PDF document text
    • http://llux.vn/uploads/files/57198874175.pdfIn PDF document text
    • http://angelcabrera.com/FCKfiles/file/jubejag.pdfIn PDF document text
    • http://madveras.com/ckfinder/userfiles/files/31528191854.pdfIn PDF document text
    • http://rracc.com/file_media/file_image/file/51833913137.pdfIn PDF document text
    • https://autoradiator.mn/uploads/ckfinder/files/69040855868.pdfIn PDF document text
    • https://veaodaibrahma.com/uploads/image/files/boxix.pdfIn PDF document text
    • https://onlinendttraining.net/files/75173164823.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/ngfLrbzwjls/uplcv?utm_term=auto+followers+ig+apkPDF 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_off0000b712.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB712 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000cf24.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCF24 16852 bytes
SHA-256: 745f788576254acd9f2d4eb2ec655d5679a77f82f4336febcce309b3ac38252d
font_02_sfnt_off0000fa1b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFA1B 10688 bytes
SHA-256: 5dc60394785586cba86c5afbe8b81b392678c49a23773344332cec5baffe6cf5