Malicious PDF — malware analysis report

Static analysis result for SHA-256 9f82fb372c0d336e…

MALICIOUS

PDF

68.8 KB Created: 2021-09-10 09:17:54 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 4075654e7cfffa2badc6a8fb67e5010f SHA-1: 2b443f623b74d5a5ee2bfe95589115cc419e71df SHA-256: 9f82fb372c0d336e4cf5ed46737766bc03f42b8a70a188412dc05948f9411fc5
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was detected by ClamAV as Pdf.Phishing.Trojan and a machine learning classifier flagged it with high confidence. Multiple heuristics indicate it functions as a link farm, directing users to numerous external PDF files hosted on potentially disposable domains. The presence of embedded URLs and the overall structure suggest an attempt to redirect users to malicious content, likely for phishing or malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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://auf.vn/wp-content/plugins/super-forms/uploads/php/files/e5dk16afc3skgbnjm72e0tbna0/96244604409.pdf In PDF document text
    • http://bjyhyy.cn/filespath/files/20210910091800.pdfIn PDF document text
    • http://floridadressyourhome.com/uploaded_files/userfiles/files/segusutozafumim.pdfIn PDF document text
    • https://raovat72.vn/uploads/news_file/poxivinej.pdfIn PDF document text
    • https://kccegis.com/upfiles/content/file/20210909023730.pdfIn PDF document text
    • http://www.radeton-cz.vasestranky.cz/ckfinder/userfiles/files/58255873887.pdfIn PDF document text
    • http://koala-al.com/d/files/sobikusudikanadudawepi.pdfIn PDF document text
    • http://architettorobertafasola.eu/userfiles/files/46580061693.pdfIn PDF document text
    • http://worldsocialistpartyindia.org/ckfinder/userfiles/files/lenabaxujubogedarajoluvu.pdfIn PDF document text
    • http://billagelaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/kolukuzujuduvewejasotam.pdfIn PDF document text
    • http://bordahusfeldolgozo.hu/editor_up/pabuta.pdfIn PDF document text
    • https://lean-ds.com/upload/editor/file/70455280000.pdfIn PDF document text
    • https://gkatsov.com/userfiles/file/90917243548.pdfIn PDF document text
    • https://paron-rebondir.com/uploads/files/43193240828.pdfIn PDF document text
    • https://mma-montessori.com/admin/ckfinder/userfiles/files/63773484585.pdfIn PDF document text
    • http://reyazahmad.bscsaoner.in/ckfinder/userfiles/files/pokejipipoxobitup.pdfIn PDF document text
    • https://idosekotthonaveresegyhaz.hu/files/files/66448594906.pdfIn PDF document text
    • http://ltptech.vn/uploads/userfiles/file/puxoka.pdfIn PDF document text
    • http://saigonford3s.com/uploads/2021-09-10/images/files/jenok.pdfIn PDF document text
    • https://mimpiindah1.com/contents/files/43884388994.pdfIn PDF document text
    • https://biroestarsa.hu/uploads/file/70913158854.pdfIn PDF document text
    • http://clearlakesd.org/wp-content/plugins/formcraft/file-upload/server/content/files/161347b65e0916---59566598447.pdfIn PDF document text
    • http://yanartekstil.com/firma/files/newamenewixativowomis.pdfIn PDF document text
    • https://hoatuoi360.vn/uploads/files/pefowojupagi.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/GLLx1DTH0VQ/uplcv?utm_term=obb+nfs+most+wantedPDF 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_off0000b1ac.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB1AC 14340 bytes
SHA-256: f31bcd521ee5a004e3b5ef746d9a988a2885d7eba7831cc7fcf065935cf713a3
font_01_sfnt_off0000d569.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD569 10528 bytes
SHA-256: 93923130644821ce25ebb24bdcaba1d10f5b79ea54b955a50249297f163db84b
font_02_sfnt_off0000ed88.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED88 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1