Malicious PDF — malware analysis report

Static analysis result for SHA-256 c4155acbef71356c…

MALICIOUS

PDF

87.9 KB Created: 2021-09-10 22:23:23 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: 37437052bb8d4e94a5e2838ebbe63782 SHA-1: e1f32648f5e7eb233c36e7d4e8a0101d09e58f1f SHA-256: c4155acbef71356c610615953e6f7c28f7a4a787bb11ab5b60a8a85060d3806c
166 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous links to external websites, many of which are hosted on disposable domains and appear to be part of a link farm. The ClamAV detection and ML classifier strongly indicate malicious intent, likely for phishing or distributing further malware. The presence of embedded URLs and the heuristic 'PDF_RANDOM_URL_LINK' suggest the document is designed to redirect users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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
  • PDF link to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://australiancaravancentre.com.au/application/third_party/ckfinder/userfiles/files/67853005885.pdf In PDF document text
    • https://whereestar.com/marinarubicon/admin/file/vunedejelolujipola.pdfIn PDF document text
    • http://masterref.ru/editorfiles/file/rirakuwobifa.pdfIn PDF document text
    • https://bearings.vn/images/ckeditor/files/vupijamosefunelafu.pdfIn PDF document text
    • http://metalzilembo.it/userfiles/files/89870561245.pdfIn PDF document text
    • http://asbazainville.org/userfiles/file/31579823530.pdfIn PDF document text
    • http://pharmorgsyn.com/upload/files/26092470977.pdfIn PDF document text
    • https://ottopianos.nl/files/nutimiwinofixebata.pdfIn PDF document text
    • http://ciccioinpentola.com/userfiles/files/xofudajikifolepopot.pdfIn PDF document text
    • http://1-sanya.com/blog_images/blog_/file/momowen.pdfIn PDF document text
    • http://rideabikenews.com/user_img/files/pilinofosowenupo.pdfIn PDF document text
    • http://tucholainfo.pl/userfiles/file/gukivefukeki.pdfIn PDF document text
    • http://security-m.jp/tool/images/file/10536000250.pdfIn PDF document text
    • https://windsbs.biz/files/file/fefawavamuwopi.pdfIn PDF document text
    • http://ambulatorioveterinariovianello.eu/userfiles/files/fixoz.pdfIn PDF document text
    • https://humanistbeauty.com/wp-content/plugins/super-forms/uploads/php/files/upcns5m3ublo7bvhe61pto3cd6/fasedijoboxofudogu.pdfIn PDF document text
    • http://gramercygrand.ru/files/file/foditewuxil.pdfIn PDF document text
    • http://lulanjina.net/upload/files/17514014623.pdfIn PDF document text
    • http://www.meglobalinc.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/161395c3625127---xemororip.pdfIn PDF document text
    • http://trackeg.com/en/wp-content/plugins/formcraft/file-upload/server/content/files/16132edf07c6b7---73366573284.pdfIn PDF document text
    • http://ebiocell.com/uploadfile/file///2021090202231624.pdfIn PDF document text
    • https://talenthunt.biz/userfiles/file/mupijakepuva.pdfIn PDF document text
    • http://canadianrockies.ca/files/file/89096673195.pdfIn PDF document text
    • http://ahkjt.com/upfile/file/29375167517.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/ngfLrbzwjls/uplcv?utm_term=android+apps+not+able+to+access+internetPDF 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_off0000f1e2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF1E2 18248 bytes
SHA-256: e4b12d4f25bd31bf7911e656b0fec82a7d5b31ddea898780a476b8a4a7bd8000
font_01_sfnt_off00012187.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12187 10628 bytes
SHA-256: a56b6fc909e6ee8697f0ac168ead46b86ca18627655a9f56eef3eecac8a7052d
font_02_sfnt_off000139bd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x139BD 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1