Malicious PDF — malware analysis report

Static analysis result for SHA-256 a8748cc540d45d79…

MALICIOUS

PDF

79.0 KB Created: 2021-09-21 05:21:57 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: c41d44f72506ab4cd51bb2af25f573ae SHA-1: 07e8acf126e9c1764131ccf58f54f3814b11633d SHA-256: a8748cc540d45d79f4a1a96c13f3acb5194aa773ebb0b09b837efb2a501bf8ea
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file flagged by ClamAV as Pdf.Phishing.Trojan and by an ML classifier as malicious. It contains numerous embedded URLs, many of which point to 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 a large number of links. While no scripts were explicitly extracted, the nature of the embedded URLs and the heuristics suggest the PDF is designed to redirect users to malicious content, likely for phishing or malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

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://adoriantarla.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1613e370255419---53162615364.pdf In PDF document text
    • http://agataklimowska.pl/userfiles/file/tododibebojak.pdfIn PDF document text
    • http://streathamtaxi.com/survey/userfiles/files/xadelamitavixisaniwediw.pdfIn PDF document text
    • https://www.hmgfinance.com/ckfinder/userfiles/files/tokaxejafif.pdfIn PDF document text
    • https://mgrenginiai.lt/ckfinder/userfiles/files/77388149470.pdfIn PDF document text
    • https://arte-salon.ru/upload_picture/80787193815.pdfIn PDF document text
    • http://multiflex.ru/userfiles/file/gileribisujiposeseme.pdfIn PDF document text
    • http://bochkari24.ru/pic/file/56816921244.pdfIn PDF document text
    • https://gencerenerji.com/resimler/files/84202039819.pdfIn PDF document text
    • http://www.musicboxpiano.com/contentfiles/96854507032.pdfIn PDF document text
    • http://hstechno.com/userData/ebizro_board/file/dedemeg.pdfIn PDF document text
    • https://bluetact.com/ckfinder/userfiles/files/48149937402.pdfIn PDF document text
    • http://mcutech.net/files/79243873436.pdfIn PDF document text
    • http://silverk.ru/img/lib/file/gosevudopawowajusajakani.pdfIn PDF document text
    • http://melissajacksonmd.com/wp-content/plugins/formcraft/file-upload/server/content/files/161338a66664ef---tepitasuximefix.pdfIn PDF document text
    • https://narellesastro.com/userfiles/files/vekesijoxolevilizodo.pdfIn PDF document text
    • http://xn--h1acbpobggs.xn--p1ai/data/files/zamopavufuzunituf.pdfIn PDF document text
    • https://geniodelweb.com/file/venukoladebadajuziti.pdfIn PDF document text
    • https://alpinashop.rudy-ra.com/files/gegezedikugometo.pdfIn PDF document text
    • https://designclarf.it/file/7480825996.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/GLLx1DTH0VQ/uplcv?utm_term=android+wallpaper+bluePDF 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_off0000d2cd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD2CD 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000eadf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEADF 17052 bytes
SHA-256: 5b57d994b8462a279afda51b531ca7394c492d47f7ce96bf90088348d9abe3cf
font_02_sfnt_off00011733.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11733 10424 bytes
SHA-256: 7652d50ceb4157162d66ad825eb03e6d7d5566fd846a2e561ee638c616d198f4

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