Malicious PDF — malware analysis report

Static analysis result for SHA-256 effd6b7c6ace0812…

MALICIOUS

PDF

82.7 KB Created: 2021-09-02 06:28:08 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 93e7152202dac6b085bdcd7c4f61edd3 SHA-1: c0d87d86a634d685e2a94ae04fe5ec4cca1490b8 SHA-256: effd6b7c6ace08128ca2c8698a783af71010d7be3964461aac4ab605fee2cb3f
96 Risk Score

Malware Insights

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

The file is a PDF that functions as a link farm, containing numerous URLs pointing to other PDF files. Several of these URLs are hosted on compromised CMS upload directories, indicating a potential distribution mechanism for malicious content. The ML classifier strongly flagged this PDF as malicious, supporting the assessment of a malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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://www.alfainstal.pl/wp-content/plugins/formcraft/file-upload/server/content/files/161255de864692---24128033503.pdf In PDF document text
    • http://xnkvinatimex.com/uploads/files/6485010797.pdfIn PDF document text
    • https://eliteplacementagency.com/uploads/files/jerofiwazerezidowuzamu.pdfIn PDF document text
    • http://sbsinternationalschool.org/userfiles/file/71367386473.pdfIn PDF document text
    • https://unitedcardsolutions.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609af6773123f---sodasugonuxof.pdfIn PDF document text
    • http://hainfelderteich.at/tobolebikarupobusopaxi.pdfIn PDF document text
    • http://suriyedostlukdernegi.org/image/files/wusogepigopeda.pdfIn PDF document text
    • http://beiks.info/public/file/ninadanewiselovosew.pdfIn PDF document text
    • http://kath-kiga-bw.de/bilder/berichte/file/61672868044.pdfIn PDF document text
    • https://www.reparaciondebomba.com.ar/wp-content/plugins/super-forms/uploads/php/files/evq54915u7rc5v3p95s5g3eui5/4416519812.pdfIn PDF document text
    • http://interstyle.org/content/xuploadimages/file/vuruginijo.pdfIn PDF document text
    • http://baheth24cars.com/ckfinder/userfiles/files/wukilokakivi.pdfIn PDF document text
    • http://aydinservis.com/ckfinder/userfiles/files/muvimibepojum.pdfIn PDF document text
    • https://www.barrau-philippe-sedeco.fr/ckfinder/userfiles/files/lilewukop.pdfIn PDF document text
    • http://www.greenbriarpropmgmt.com/wp-content/plugins/super-forms/uploads/php/files/b9525b8020dcb2ca322325a1545255be/55026393667.pdfIn PDF document text
    • http://izdo.org/img/userfiles/files/bukawilubiduxuforegupot.pdfIn PDF document text
    • http://maskaevlawyer.ru/userfiles/file/43805865959.pdfIn PDF document text
    • https://comtraining.cl/userfiles/files/kinakexaledixifebexen.pdfIn PDF document text
    • http://av-jet.ru/userfiles/file/gobamajorakizinili.pdfIn PDF document text
    • http://motolargo.pl/userfiles/file/51628897054.pdfIn PDF document text
    • http://profil-metall.de/content/uploads/file/nanusis.pdfIn PDF document text
    • http://www.mywil.ch/wp-content/plugins/formcraft/file-upload/server/content/files/160b24f1456efb---39656461865.pdfIn PDF document text
    • http://juha.be/_files/file/93503635654.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/3CAf4wW3hvY/uplcv?utm_term=class+10+chemistry+pdf+downloadPDF 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_off0000e012.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE012 11292 bytes
SHA-256: beee7f4d082f36aef08ff3871069f7bb96f50e881bc82753f39142d2fcffe6c3
font_01_sfnt_off0000fa81.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFA81 16440 bytes
SHA-256: 0db1ccc449b6980ee4d6182d6c655353765ce352281b39e46393b6e26c5ee2dd
font_02_sfnt_off000124ec.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x124EC 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1