Malicious PDF — malware analysis report

Static analysis result for SHA-256 81bf5671c4f5a7bc…

MALICIOUS

PDF

77.4 KB Created: 2021-09-09 01:35:58 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 22835b3c840be86d8637e1847ed2202f SHA-1: 6044680173d4cc43b4d462ede2403e17bb2ac137 SHA-256: 81bf5671c4f5a7bc4e45391adedb64edcff6a368bdcb8f8a6c9e86cdf2d63b89
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF file was flagged by ClamAV as a phishing trojan and ML classifiers indicated a high probability of maliciousness. Heuristics identified the document as a link farm, with numerous external URIs pointing to potentially compromised or disposable hosting. The presence of multiple PDF_SEO_DISPOSABLE_LINK_FARM and PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM firings strongly suggests a malicious intent to redirect users to harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9953

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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://queure.ru/uplcv?utm_term=android+10+ui+kit+figma PDF link annotation
    • http://hoangnampte.vn/quangbasanpham/app/webroot/upload/image/files/fitafo.pdfIn PDF document text
    • http://lachambredechos.com/userfiles/file/69811516776.pdfIn PDF document text
    • https://lanna-flyingclub.com/ckfinder/userfiles/files/binex.pdfIn PDF document text
    • http://prestinoequitacion.com/imagenes/upload/files/25554771323.pdfIn PDF document text
    • http://reclaimsplus.com/wp-content/plugins/super-forms/uploads/php/files/860d8eaef2d6c1db7e80bc461eefb58d/wepalumubebaxetej.pdfIn PDF document text
    • https://hongmao.tw/uploads/files/202109011804596454.pdfIn PDF document text
    • https://golf-tout-terrain.com/publish/page/file/rowawosupesi.pdfIn PDF document text
    • http://megalaserasia.com/upload///4060920313.pdfIn PDF document text
    • http://sarkar.ie/userfiles/file/29093671827.pdfIn PDF document text
    • http://chonburi33.com/userfiles/file/gufarutarasuka.pdfIn PDF document text
    • http://dgelc.com/userfiles/file/20210908195459.pdfIn PDF document text
    • https://louvre.lv/res/wysiwyg/file/pejijikekafolesajodil.pdfIn PDF document text
    • http://hotelniagararimini.eu/userfiles/files/47038667972.pdfIn PDF document text
    • https://shatalarab-llc.net/userfiles/files/85119988986.pdfIn PDF document text
    • http://maxitelt.no/wp-content/plugins/formcraft/file-upload/server/content/files/16139389a94de1---69901012060.pdfIn PDF document text
    • http://tobn56.com/UpFiles/file/49396025706.pdfIn PDF document text
    • http://musicpark-live.de/userfiles/file/setibefubapojofelotem.pdfIn PDF document text
    • http://milcontabil.com.br/wp-content/plugins/super-forms/uploads/php/files/tu122mn7e81iphu4f8pve1i0q6/67134590688.pdfIn PDF document text
    • http://www.haztartasigepszakuzlet.hu/pics/file/subasawitebana.pdfIn PDF document text
    • http://ewhamd.net/upFiles/ckeditor/files/92306819252.pdfIn PDF document text
    • http://dlastudenta.org/Upload/file/7463464757.pdfIn PDF document text
    • https://doitsolutions.co/wp-content/plugins/super-forms/uploads/php/files/c155f6636c80cdfa4047271cee27ebfb/jutejozetup.pdfIn PDF document text
    • http://colafranceschi.it/userfiles/files/lokotobopusemazuwevasipa.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_off0000ca67.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCA67 17600 bytes
SHA-256: 99e51f4e37326eac79873187d75ec79f82e8781880befb41eba8d8a817b76235
font_01_sfnt_off0000f801.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF801 10696 bytes
SHA-256: d0867565a5e60651772514388d680fb2c31aba259976f7c6fb3adeab07f20379
font_02_sfnt_off00011068.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11068 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1