Malicious PDF — malware analysis report

Static analysis result for SHA-256 8d109bcb1ac9aa4d…

MALICIOUS

PDF

77.1 KB Created: 2021-09-18 23:35:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-21
MD5: a32caf3cf3669eeeeece9c90deb2c2bf SHA-1: 6dec2a4a75ab0d24bc6dffcd1e598933dd2daf78 SHA-256: 8d109bcb1ac9aa4dd6293d298d02327e8f765b25ac52133a0095908ff0a9e972
166 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by ClamAV as Pdf.Phishing.Trojan and a machine learning classifier indicated a high probability of maliciousness. Heuristics identified the document as a link farm with numerous external URIs, many pointing to disposable hosting. The presence of 'wkhtmltopdf' in the metadata suggests it was generated by a tool, potentially to obscure its true nature. While no scripts were explicitly extracted, the PDF structure and embedded URLs strongly suggest an intent to redirect users to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9985

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • LOLBin token sequence in document text high SE_LOLBIN_RUN_COMMAND
    Extracted document text contains a Windows script/execution tool name (PowerShell, mshta, cmd, rundll32, regsvr32, …) within 220 characters of a dangerous flag, command verb, or URL. This is a visible 'run this' instruction in HTML/PDF/RTF lure bodies, or — in macro-laden Office files — the macro's own string-pool entries appearing adjacent in extracted text.
  • 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://slide-bearing.com/d/files/85223725292.pdf In PDF document text
    • http://live-lessons.net/lcj/web/uploads/assets/file/15477692455.pdfIn PDF document text
    • https://www.audioclinica.pt/wp-content/plugins/super-forms/uploads/php/files/upl2ccnmdd6t35cdelgg069r7g/kutixowedizusik.pdfIn PDF document text
    • https://pierreseche.fr/userfiles/file/gojibaboxup.pdfIn PDF document text
    • https://ijpdua.com/contents/files/gejamananidap.pdfIn PDF document text
    • http://business-plan-capalpha.eu/mbp/upload/images/images/upload/ckfinder/xitijewun.pdfIn PDF document text
    • http://huthamcauquanggiap.com/upload/files/mitazudiwasobufitaberobi.pdfIn PDF document text
    • https://netron.pt/app/webroot/media/files/sewenumonaliwadopipafedu.pdfIn PDF document text
    • https://vinacomvietnam.vn/uploads/news_file/58401885343.pdfIn PDF document text
    • https://delcinfo.ru/img/files/files/vulugabomubipirukajek.pdfIn PDF document text
    • http://putzlappenborner.at/editor_up/39517745484.pdfIn PDF document text
    • https://corpusbg.com/files/fck/file/gijomugajirukopogatafano.pdfIn PDF document text
    • https://laneopx.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613173deef63e---46052481563.pdfIn PDF document text
    • https://kidneystonetreatment.in/userfiles/files/93196720856.pdfIn PDF document text
    • http://cleversystems.ru/userfiles/file/mufekav.pdfIn PDF document text
    • http://ozgu-yapi.com/firma/files/84066892164.pdfIn PDF document text
    • https://anjingliar.com/contents/files/gexof.pdfIn PDF document text
    • http://coral-travel66.ru/admin/ckfinder/userfiles/files/xejakogefupub.pdfIn PDF document text
    • https://simon-daulte.com/ckfinder/userfiles/files/14000053046.pdfIn PDF document text
    • http://charmingcurls.se/upload/file/vemuxeniwikagur.pdfIn PDF document text
    • http://hauptlawoffice.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/tegofabid.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/6naE_Nh8_CY/uplcv?utm_term=parallel+space+2017PDF 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_off0000c9b4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC9B4 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000e1c6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE1C6 17784 bytes
SHA-256: cec17eaa1702c8aae8f483f9a0872f1e40b112d7d60ce1f061090175c5cb0b26
font_02_sfnt_off00010f93.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10F93 10300 bytes
SHA-256: 747ea16462dfaa662aed8c087fa6462ce53d221b00258d720b489779a5c6f4b5