Malicious PDF — malware analysis report

Static analysis result for SHA-256 51913be988661fa9…

MALICIOUS

PDF

81.5 KB Created: 2021-09-18 15:00:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 81d82dd505ef611eb6d9fde21633cd57 SHA-1: ae4dbea83b870b2a1578657e0dcc93f88dc6a9d4 SHA-256: 51913be988661fa9559bf2e08004eaa0b834090b223cb8316f3fc3638f6e4807
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs that point to various PDF files hosted on different domains, suggesting a link farm designed to distribute malicious content. The ML classifier and ClamAV detection strongly indicate malicious intent, likely phishing or malware delivery. Although no scripts were explicitly extracted, the PDF structure and embedded URIs are indicative of malicious activity.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9949

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://infrive.ru/uplcv?utm_term=download+graph+paper+pdf PDF link annotation
    • https://bodegoncriollo.com/userfiles/file/45612287552.pdfIn PDF document text
    • https://vakukh.ru/wp-content/plugins/super-forms/uploads/php/files/4681b06a257c44e9d8e001aa51352b14/fugugivotib.pdfIn PDF document text
    • https://whatshoulditcostme.com/userfiles/file/19763263864.pdfIn PDF document text
    • https://nada70.org/userfiles/file/xipirozoko.pdfIn PDF document text
    • http://ppfi-online.com/userfiles/file/24352906390.pdfIn PDF document text
    • http://remont-elektro.eu/archiv/file/76773992751.pdfIn PDF document text
    • http://litho-and-co.fr/ckeditor/upload/files/bemamiji.pdfIn PDF document text
    • https://millinerandassoc.com/files/file/67440956976.pdfIn PDF document text
    • http://www.absolutecateringla.com/wp-content/plugins/formcraft/file-upload/server/content/files/16137a0038efa0---wezutolele.pdfIn PDF document text
    • http://azseal.net/uploads/userfiles/file/79243728208.pdfIn PDF document text
    • http://fujavietnam.com/images/Download/29098057702.pdfIn PDF document text
    • https://perfecthospital.org/FCKeditor/file/puvawoxidakazulegenuwa.pdfIn PDF document text
    • http://www.emporiocaritaspisa.it/wordpress/wp-content/plugins/formcraft/file-upload/server/content/files/16131bad6b53c4---jipuzisipo.pdfIn PDF document text
    • http://tfe-design.dk/userfiles/file/42381626766.pdfIn PDF document text
    • http://theseadiaries.com/ckfinder/userfiles/files/8145064007.pdfIn PDF document text
    • http://www.me.ntou.edu.tw/ckfinder/userfiles/files/20210907_111516.pdfIn PDF document text
    • http://havefuntogether.com/image/upload/File/63835984587.pdfIn PDF document text
    • https://kontiko.com/ktkweb3/images/upload/files/wilej.pdfIn PDF document text
    • http://saatgaamkansarasamaj.com/admin/uploads/files/pusifuwateranate.pdfIn PDF document text
    • https://stancijanegrin.com/UserFiles/files/25904986832.pdfIn PDF document text
    • https://tinnituskozpont.hu/files/57353437831.pdfIn PDF document text
    • http://joinsocialbubble.com/cake/beta/userfiles/file/vozararokufi.pdfIn PDF document text
    • http://studiolorenzino.eu/userfiles/files/tofipijifonexekuvobaxadi.pdfIn PDF document text
    • https://aawyx.com/sites/default/imageuser/file/88032483484.pdfIn PDF document text
    • https://nikken-engineer.jp/export/sd205/www/jp/r/e/gmoserver/8/6/sd0748886/nikken-engineer.jp/fckeditor/upload/file/6594418817.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_off0000dc25.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDC25 10504 bytes
SHA-256: 6ab5a48754251ed5b57405f1b6e1e140905c1211835e8f706ab6f85bef965e02
font_01_sfnt_off0000f3c7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF3C7 17140 bytes
SHA-256: 91a05d9d4c5bd59988e77efd7c43ce354a4e49602576402ba0cc27f8b839200b
font_02_sfnt_off0001204d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1204D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1