Malicious PDF — malware analysis report

Static analysis result for SHA-256 c9cfff260d664286…

MALICIOUS

PDF

84.1 KB Created: 2021-09-11 12:36:17 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 91522c06d4d4e1ef72693ec13f0e25a8 SHA-1: 3a59ff97356136b9fe2fdde3a0764c200a077a98 SHA-256: c9cfff260d66428647073be280abbd20d5f1ec2290c37985dbc5a098ae2cb6f7
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The ML classifier strongly indicates maliciousness, supported by heuristics identifying the PDF as a link farm pointing to compromised CMS uploads and disposable hosting. The document body is heavily obfuscated, preventing a clear understanding of its specific lure. However, the numerous external links suggest an attempt to redirect users to potentially malicious sites or for SEO manipulation.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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 https://otoform.com/upload/ckfinder/files/nazeti.pdf In PDF document text
    • https://jeevandeepspecialcare.com/ckeditor/ckfinder/userfiles/files/14620151996.pdfIn PDF document text
    • http://gu-bo.cn/uploads/files/4354366328.pdfIn PDF document text
    • http://sushi-belovo.ru/files/duterabidoxovuwido.pdfIn PDF document text
    • https://dennismaloney.ca/upload/editor/file/6732172368.pdfIn PDF document text
    • http://compsult.net/userfiles/file/xizosopu.pdfIn PDF document text
    • https://www.horisunmauritius.com/wp-content/plugins/super-forms/uploads/php/files/88ef45296876efe0da745814c5107449/52507573094.pdfIn PDF document text
    • http://unibox.lv/files/text/39520938362.pdfIn PDF document text
    • http://cheers-gifts.com/userfiles/betifero.pdfIn PDF document text
    • http://generoussecurity.com/uploads/63547871598.pdfIn PDF document text
    • https://lostfoundglobal.com/userfiles/file/56833781191.pdfIn PDF document text
    • http://swhos.com/upload/files/vasomox.pdfIn PDF document text
    • https://venusnvs.com/userfiles/file/77509409361.pdfIn PDF document text
    • http://dabien.co.kr/wp-content/plugins/formcraft/file-upload/server/content/files/1612f452381732---gasugemunegefix.pdfIn PDF document text
    • https://endobible.com/userfiles/file/23195425535.pdfIn PDF document text
    • http://progettarecasa.com/userfiles/files/vutezisesidel.pdfIn PDF document text
    • http://bastola.org/userfiles/file/41914136481.pdfIn PDF document text
    • http://kondicionery-vidnoe.ru/upload_picture/file/37234608678.pdfIn PDF document text
    • http://solmoda.it/userfiles/files/muvesavofefaluvuvup.pdfIn PDF document text
    • http://yjccnc.com/upload/files/mipuseriwopu.pdfIn PDF document text
    • http://gartenstadt-apotheke.com/userfiles/file/81029512896.pdfIn PDF document text
    • https://advicezone.org.uk/wp-content/plugins/super-forms/uploads/php/files/vhr7jkvd3sngi8ujjqgj242va5/2599559197.pdfIn PDF document text
    • https://soportedevida.mx/ckfinder/userfiles/files/nuzojakumekuvafoki.pdfIn PDF document text
    • http://maslatalaia.com/userfiles/file/falurejexuv.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/1KS0DP0cxss/uplcv?utm_term=how+to+fix+android+process+acorePDF 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_off0000e32e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE32E 17948 bytes
SHA-256: 875c7f94439c045b9b951b3526f5fedcb3756e9a12e8a922333fc5c084bc4a3f
font_01_sfnt_off00011166.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11166 10744 bytes
SHA-256: bdd8ad5f0afadea035dbd142899f8f7daaf0df20d159592f3c1f6febf0ee2742
font_02_sfnt_off00012a49.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12A49 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1