Malicious PDF — malware analysis report

Static analysis result for SHA-256 813b7a6c3cd1bb3b…

MALICIOUS

PDF

87.7 KB Created: 2021-07-30 17:23:43 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 4a1f27704b7913c04ea8f2f4851943cf SHA-1: a690620ed60af192b77ba750a0e6ce352fabf70d SHA-256: 813b7a6c3cd1bb3b95003ea4017adc636ec3ad21890460dcf4975c2df116603a
96 Risk Score

Malware Insights

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

The sample is identified as malicious by an ML classifier and exhibits characteristics of a link farm. It contains numerous embedded URLs, many of which point to PDF files hosted on compromised WordPress sites. The primary purpose appears to be SEO manipulation or hosting malicious content, leveraging compromised infrastructure to distribute further payloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

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://az4group.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1609f04409a9b7---96621592788.pdf In PDF document text
    • http://zartmobilia.com/userfiles/file/20210719012118.pdfIn PDF document text
    • http://xn----gtbercbfedtm3b.xn--p1ai/admin/ckfinder/userfiles/files/9750328880.pdfIn PDF document text
    • http://studioaba.net/userfiles/files/watibutojosim.pdfIn PDF document text
    • https://jiptv.nl/wp-content/plugins/super-forms/uploads/php/files/s02r3eon2qf3vqnh8cjkfge0dm/95768144220.pdfIn PDF document text
    • http://schodylux.pl/userfiles/file/joxatifegevelosarufojefi.pdfIn PDF document text
    • http://nuyewrecruitment.com/wp-content/plugins/super-forms/uploads/php/files/3cddd52b90c2b4ce48b5937ee2bd4214/ditozija.pdfIn PDF document text
    • https://pyhm.ca/wp-content/plugins/super-forms/uploads/php/files/gonnavhb0d36r47j9mv9vd1t6g/96965858259.pdfIn PDF document text
    • https://www.allterra.group/wp-content/plugins/super-forms/uploads/php/files/58ebf580c650225c39342f01e7ea49bc/vobire.pdfIn PDF document text
    • https://xo-sound.ru/userfiles/file/16703747923.pdfIn PDF document text
    • https://songhong-thudo.com/img/files/likavodijenerajupuwe.pdfIn PDF document text
    • http://candientu24h.vn/webroot/img/files/62873188072.pdfIn PDF document text
    • https://www.sevgiliyevideo.net/wp-content/plugins/formcraft/file-upload/server/content/files/160848ee6a64e5---10326445185.pdfIn PDF document text
    • https://dungcuruamui.com/wp-content/plugins/super-forms/uploads/php/files/oem78osnkmf864fg0444ms4apl/43987888390.pdfIn PDF document text
    • http://caythuocdangian.net/images/files/vimozo.pdfIn PDF document text
    • https://ballestermultiservicios.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a6cb2972960---37964064842.pdfIn PDF document text
    • http://dolphinkorea.com/files/files/taberuvarubomajafi.pdfIn PDF document text
    • http://50wj66.com/clients/a/af/af9d65f11c1965a5434adcd4cd578f00/File/ziwunora.pdfIn PDF document text
    • https://dfa-finanz.de/wp-content/plugins/formcraft/file-upload/server/content/files/160d90522f113f---kajotiwukunimija.pdfIn PDF document text
    • http://gildiamasterov.ru/userfiles/file/ziwaxeni.pdfIn PDF document text
    • http://prestinoequitacion.com/imagenes/upload/files/vemoxekanatasobeloposod.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/GLLx1DTH0VQ/uplcv?utm_term=helen+fisher+personality+test+compatibilityPDF 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_off0000f345.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF345 10988 bytes
SHA-256: caeae303e81d7e725833aa215ff2c70c8b51562e2d48b8bc8d8638dfa14c832a
font_01_sfnt_off00010c62.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10C62 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012474.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12474 16832 bytes
SHA-256: 682ca38a69fd5259b13945ad5c59ae8283c85618e79f4e0d59c08995bf9a4931