Malicious PDF — malware analysis report

Static analysis result for SHA-256 040cd73aedf3b176…

MALICIOUS

PDF

79.4 KB Created: 2021-09-17 07:09:09 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 5390b3b9772360d167a12d26a0e09c62 SHA-1: c8bb2907a7d42b6e856b6f917a5b31cc244bb05f SHA-256: 040cd73aedf3b176a64b4b944c1a657c1fed4c6b6c46641e8d2ae64e3f124f22
146 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains malformed streams and numerous external URIs, indicating it's designed to redirect users to potentially malicious websites. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or malware distribution. Although no scripts were explicitly extracted, the PDF structure and URI usage are consistent with techniques used to deliver second-stage payloads or redirect to phishing sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

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
  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • 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://vhcvietnam.vn/ckeditor/images/files/lewixifixes.pdf In PDF document text
    • http://woodlander.sk/grafika/file/dakuwe.pdfIn PDF document text
    • https://perfecthospital.org/ckfinder/userfiles/files/7812402209.pdfIn PDF document text
    • http://www.sunarsurdurulebilir.com/wp-content/plugins/super-forms/uploads/php/files/7qoqk85tti96qgjs4ecdq3vec7/vuwirixajis.pdfIn PDF document text
    • http://mjengo.org/FCKeditor/editor/filemanager/connectors/php/connector.php?Command=FileUpload&Type=File&CurrentFolder=%2Ffile/nesojemal.pdfIn PDF document text
    • http://eko-uklid.com/files/file/fokumatoguwejoramisiba.pdfIn PDF document text
    • http://nktrading.qa/file/files/lexivugebalurefaxifonop.pdfIn PDF document text
    • http://gdgom.com/upload/file/2109051332515233815dgrn3g0temc.pdfIn PDF document text
    • http://weilandvloeren.nl/fckimages/86904646552.pdfIn PDF document text
    • https://lesura.net/userfiles/file/nubakarov.pdfIn PDF document text
    • https://www.clubmanizales.com.co/wp-content/plugins/formcraft/file-upload/server/content/files/1612f3ceb0d895---rutudi.pdfIn PDF document text
    • http://memsports.com.br/admin/libs/ckeditor/ckfinder/files/lubon.pdfIn PDF document text
    • http://novosib-sport.ru/ckfinder/userfiles/files/wubenamim.pdfIn PDF document text
    • http://korvet-sp.ru/userfiles/file/43109022422.pdfIn PDF document text
    • http://csaladiegyteruautok.hu/userfiles/files/35952582708.pdfIn PDF document text
    • http://miyagi.chi-kara.net/Upload/files/tubakanoziralufogivem.pdfIn PDF document text
    • http://yenidenyuzlendirme.com/ckfinder/userfiles/files/wawuzujepolof.pdfIn PDF document text
    • http://dulichtantai.com/files/uploaded/files/9256477690.pdfIn PDF document text
    • https://www.artikel238.nl/emmwebbit/resources/ckfinder/userfiles/files/19970709363.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/S30rS-6n6vg/uplcv?utm_term=windroy+windows+10+64+bitPDF 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_off0000d18b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD18B 10652 bytes
SHA-256: 1f0721246daaccbd5e4cd36a7b097e2f46a4cfa4140844a8987d803b6a6dc691
font_01_sfnt_off0000ea21.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEA21 17980 bytes
SHA-256: 171cac4aecdc4f92f03a6c57d3a91bf8fc1efc28edc71d84b826dadd0c973d6b
font_02_sfnt_off0001187c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1187C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1