Malicious PDF — malware analysis report

Static analysis result for SHA-256 528e163ae68456f5…

MALICIOUS

PDF

87.1 KB Created: 2021-09-09 11:09:31 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: e4488404321320dee6e78fd16059c7d7 SHA-1: c989812f752c8d14001f3542c585479432095aad SHA-256: 528e163ae68456f5558a307a071d161e37899bcf884b16c3fb8074b3f637877f
126 Risk Score

Malware Insights

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

The sample was detected as a malicious PDF by ClamAV and an ML classifier. It contains numerous embedded URLs, many of which point to external PDF files hosted on various domains, suggesting a link farm or redirection mechanism. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic indicates a pattern of using disposable hosting for these links, which is common in phishing and malware distribution campaigns. The presence of these external links strongly suggests the PDF is intended to redirect the user to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

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://www.smartlandgroup.com/ckfinder/userfiles/files/31022281960.pdf In PDF document text
    • http://cathugo-yachts.de/res/wysiwyg/file/42444199237.pdfIn PDF document text
    • http://yangs-ns.com/ckfinder/userfiles/files/20210904083651.pdfIn PDF document text
    • http://selmanoglusigorta.com/userfiles/file/57596204885.pdfIn PDF document text
    • http://hsaltsj.com/uploads/files/90969058920.pdfIn PDF document text
    • http://healthywithhart.com/res/file/44693024881.pdfIn PDF document text
    • http://kingsfinancialconsulting.com/userfiles/file/67761527562.pdfIn PDF document text
    • http://irina-beha.com/ckfinder/userfiles/files/rigelevenudo.pdfIn PDF document text
    • https://travels-ukraine.com/wp-content/plugins/formcraft/file-upload/server/content/files/16139b98b98c8e---19374131066.pdfIn PDF document text
    • https://detectiveoffice.net/userfiles/file/xeroroxemaf.pdfIn PDF document text
    • https://saglamahsapkutu.com/img/editor/image/file/75973574364.pdfIn PDF document text
    • http://mybed.tw/uploads/files/202109081554152595.pdfIn PDF document text
    • https://vpmemorial.net/images/file/vabilebawowamosokovu.pdfIn PDF document text
    • http://cargologicru.com/sadm_files/42536702694.pdfIn PDF document text
    • http://abimobiliare.pl/pliki/File/35644717294.pdfIn PDF document text
    • http://evrokomplekt.ru/userfiles/file/repuw.pdfIn PDF document text
    • http://southerncross-ex.com/images/blog/file/95534928748.pdfIn PDF document text
    • http://wsm.hk/images/files/gatoxotinufuxuj.pdfIn PDF document text
    • https://mexico-airport-transfers.com/ckfinder/userfiles/files/83748844415.pdfIn PDF document text
    • https://groupunsur4.com/contents/files/27021769402.pdfIn PDF document text
    • http://naitikfashions.com/ckfinder/userfiles/files/46424471018.pdfIn PDF document text
    • http://studioesflores.pl/obrazy/file/nevapag.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/6naE_Nh8_CY/uplcv?utm_term=rpg+turn+based+games+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_off0000f221.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF221 16992 bytes
SHA-256: e9121394f008e586fb60f80ec658956840ff63e18e24c5a23991f69ed1fb7f32
font_01_sfnt_off00011e4b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11E4B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00013662.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13662 10972 bytes
SHA-256: f31210d480deb5d505ca428e473251405c7a4d91b09ba448a61da8a8c39d4357

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