Malicious PDF — malware analysis report

Static analysis result for SHA-256 b4396a7debec5bb8…

MALICIOUS

PDF

80.8 KB Created: 2021-08-16 17:44:43 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: cd9c00e572bd8f0737ba5465513724b7 SHA-1: 467ae0f7868114483ebc012ee5f45391d021a931 SHA-256: b4396a7debec5bb8901e24b4166b5299111965fba9821514adbb33f79a220d8d
96 Risk Score

Malware Insights

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

The PDF file contains numerous embedded URLs, many of which point to disposable hosting or compromised CMS upload directories, indicating a link farm designed to redirect users. The ML classifier strongly flagged this PDF as malicious, supporting the assessment that it is intended to lead users to potentially harmful content or further stages of an attack. No scripts were extracted, and the document body was unreadable binary data.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

Heuristics 5

  • 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 http://cuatudongsaigon.net/uploads/files/8716918850.pdf
    • http://leaguengn.com/userfiles/file///53582668418.pdf
    • http://claudiodauelsberg.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16085074d99ca2---jikaper.pdf
    • http://isystemlab.com/admin/ckfinder/userfiles/files/nanujabupeb.pdf
    • http://novichiha.ru/pic/file/duwarabibigagus.pdf
    • http://spc1962reunion.com/clients/c/c5/c535eb5d361035e84cedf1152ec4da8f/File/muzugafovawuzotubolig.pdf
    • https://discoverapartmentsforrent.com/wp-content/plugins/super-forms/uploads/php/files/b8332a1b26921a9656d0dad6d269d339/lolutamugixufajami.pdf
    • https://rumahbaruku.com/contents//files/kabowabitadedexefazub.pdf
    • http://jointrilogy.com/wp-content/plugins/formcraft/file-upload/server/content/files/160967a14a6202---xabilagagogepepemowogowu.pdf
    • https://sonntag-immobilien.lu/userfiles/files/16584524094.pdf
    • http://shukokai-voves.fr/userfiles/file/zufotowufudemolejaz.pdf
    • http://scbczy.cn/up_files/file/20210804_160454.pdf
    • http://thongthien.vn/upload/files/14645183624.pdf
    • http://sieckultury.pl/wp-content/plugins/super-forms/uploads/php/files/62fbf229b5f03393ed6632668b1bda6d/99055728603.pdf
    • http://21cedu.com/pds/userfiles/files/zerep.pdf
    • http://aqcons.vn/upload/files/97060417289.pdf
    • https://associazionebriciole.it/public/file/65817680596.pdf
    • http://ipvoicenj.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a9e1bb83c3f---83114716048.pdf
    • http://bubblesoflove.net/wp-content/plugins/formcraft/file-upload/server/content/files/1609b772198a5d---10506466674.pdf
    • http://beiwendq.com//data/attachment/file/72000249472.pdf
    • http://dentherapia.hu/files/file/45437400868.pdf
    • http://stananddiane.com/clients/6/67/672a2699e369d648dd23e03de9deda78/File/86025177067.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/GLLx1DTH0VQ/uplcv?utm_term=pdf+to+cdr+format+online+free
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d8f5.bin
61750f714e0b127c0a2625f7c43417dbc37518e20023b9fa21a54c5793ef92f7
pdf-font-stream PDF embedded font (sfnt) at offset 0xD8F5 17200 bytes
font_01_sfnt_off000105bb.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x105BB 16792 bytes
font_02_sfnt_off00011dd2.bin
b5a6f9a9e7a343e4e5f92310e1ae55b917ebcd3ae68a3b5aaf1740c17ad5c739
pdf-font-stream PDF embedded font (sfnt) at offset 0x11DD2 10468 bytes