Malicious PDF — malware analysis report

Static analysis result for SHA-256 9f455c1af41b3b65…

MALICIOUS

PDF

71.5 KB Created: 2021-09-12 22:29:47 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-31
MD5: 75161b467bd1ba1cb59b5f22c53fc6b6 SHA-1: f787d6792c5aff3680a94280ff7408659cd723cc SHA-256: 9f455c1af41b3b659d665d7516207b61a3c1c362e89a5d7fe0f9e94bbc09a178
96 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs pointing to other PDF files hosted on compromised WordPress sites and disposable domains. This pattern suggests the document is part of a link farm designed to redirect users to malicious content, likely for phishing or malware delivery. The ML classifier strongly indicated maliciousness.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

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://krisoc.ru/uplcv?utm_term=pokemon+mega+power+cheats+items PDF link annotation
    • http://medica-brno.com/files/44577231952.pdfIn PDF document text
    • https://www.opdrrustukalac.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613b1b7836e9d---10761107612.pdfIn PDF document text
    • https://jmclimatizacionhvac.cl/images/subidas/file/21089971676.pdfIn PDF document text
    • http://onlinetalk.jp/app/webroot/img/fckfiles/file/40093480284.pdfIn PDF document text
    • http://tdsns.ru/userfiles/file/81764286442.pdfIn PDF document text
    • http://kvrhousing.com/uploads/29824862248.pdfIn PDF document text
    • http://sinoscaform.com/upload/ckimg/files/202109060903051673.pdfIn PDF document text
    • https://paymentor.nl/uploads/file/bapotadedeximafela.pdfIn PDF document text
    • http://jubileejec.com/userfiles/files/gavajufatexefakimadin.pdfIn PDF document text
    • http://ipvoicenj.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612ff0b4cb1b7---tabipo.pdfIn PDF document text
    • https://keyword-lda.pt/site/upload/file/zizirerif.pdfIn PDF document text
    • http://krevue.cz/UserFiles/File/gubuv.pdfIn PDF document text
    • https://jdbailbonds.com/wp-content/plugins/super-forms/uploads/php/files/8fb551257cb1dec8fc73a56fdac9c59e/71681180695.pdfIn PDF document text
    • https://duproject.com/uploadEditor/files/kokudobuvudafa.pdfIn PDF document text
    • https://ngusacdon.com/upload/files/41305567274.pdfIn PDF document text
    • http://kindervakantieweekdeurne.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16133425445193---nejufo.pdfIn PDF document text
    • http://scherzerpc.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/54156841029.pdfIn PDF document text
    • http://freetourscadiz.com/ckfinder/userfiles/files/44460280440.pdfIn PDF document text
    • https://nisahanpin.com/calisma2/files/uploads/mawewujanifelu.pdfIn PDF document text
    • https://haps.company/wp-content/plugins/super-forms/uploads/php/files/2b546ba781a820e0387cbb454692d3e6/wodoladugemawisogur.pdfIn PDF document text
    • https://prcomponents.com/ckfinder/userfiles/files/16902974988.pdfIn PDF document text
    • http://romanasulcikova.cz/userfiles/30660043386.pdfIn PDF document text
    • https://apartmani-mestrovic-krk.hr/files/88760161854.pdfIn PDF document text
    • 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_off0000b1e5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB1E5 10956 bytes
SHA-256: 8b1d3efa0a203ab7777c562c31fdf227e6dbbfb768ced067138775796be6c04b
font_01_sfnt_off0000cb3a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCB3A 17552 bytes
SHA-256: 655358f4335a4f881c198b351a2e4aa3d4e882ca698fd2d372a39629bebd957d
font_02_sfnt_off0000f8ad.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF8AD 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1