Malicious PDF — malware analysis report

Static analysis result for SHA-256 9b5f439a5f7c8cab…

MALICIOUS

PDF

72.2 KB Created: 2021-05-23 15:25:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-24
MD5: f44162e71fe341ebe87417fdbb7be79f SHA-1: e1a07c9534e306a3d29aa4511b3eb872d9443c5e SHA-256: 9b5f439a5f7c8cab3cdcab3c0a7d0b7ae26e98eb83c752468497cd14bc8a5b85
104 Risk Score

Malware Insights

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

The sample is a PDF document identified as malicious by an ML classifier. It contains numerous links pointing to compromised WordPress sites, specifically within plugin upload directories, indicating a link farm or redirection scheme. The presence of a 'download button' lure further suggests an attempt to trick the user into clicking a link. The document body is heavily obfuscated and contains metadata from wkhtmltopdf, but the primary malicious functionality appears to be the distribution of links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • 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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://www.helmmsp.ca/wp-content/plugins/super-forms/uploads/php/files/f3467848533206d84137ca6ac01175d8/segobidejugogafevemeje.pdf In PDF document text
    • http://sh8ke.com/wp-content/plugins/formcraft/file-upload/server/content/files/16076f4edde4a9---tufubepasigonafarutuxaw.pdfIn PDF document text
    • https://janeunchained.com/wp-content/plugins/super-forms/uploads/php/files/18e1pr1hod7drniq7ohbrfg1v3/219278319.pdfIn PDF document text
    • http://www.dadosefatos.net.br/wp-content/plugins/formcraft/file-upload/server/content/files/1608b85dd0910e---17580572733.pdfIn PDF document text
    • https://elitteaccesorios.com/wp-content/plugins/super-forms/uploads/php/files/h2715pvujvisrqr5okgde6eg2a/47250692705.pdfIn PDF document text
    • http://kino-profi.com/wp-content/plugins/super-forms/uploads/php/files/7360610d665676074006132931643eea/giwirasevux.pdfIn PDF document text
    • http://www.191seo.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608e9460acf01---xoletexekivurepadel.pdfIn PDF document text
    • https://bamfieldrental.com/userfiles/file/rivoruvu.pdfIn PDF document text
    • https://www.masismarketing.com/wp-content/plugins/super-forms/uploads/php/files/82d7b02f42a1acba61d4529d3c690e5b/jifexali.pdfIn PDF document text
    • http://mfplus.ba/wp-content/plugins/formcraft/file-upload/server/content/files/1607b7164bbac0---sipesaliguxu.pdfIn PDF document text
    • http://www.victorian-manor.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/1606d8fa99014b---28166547820.pdfIn PDF document text
    • https://archcosmeticstudio.com.au/wp-content/plugins/super-forms/uploads/php/files/815efdcd6781bb02cd18bf290a1b523d/22430574070.pdfIn PDF document text
    • https://plumcourse.com/wp-content/plugins/super-forms/uploads/php/files/84057e42faaaf0a1797d318103923968/86283753265.pdfIn PDF document text
    • http://multiseal.com.ph/wp-content/plugins/formcraft/file-upload/server/content/files/16078e862ca69f---54224045359.pdfIn PDF document text
    • http://ahsaipu.com/v15/Upload/file/2021581827228694.pdfIn PDF document text
    • https://readxyz.com/wp-content/plugins/super-forms/uploads/php/files/71cb7076e06549a1060549c6776889eb/42832744090.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/DOqCt-cVA4I/uplcv?utm_term=what+to+use+for+egg+drop+experimentPDF 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000dd19.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD19 5504 bytes
SHA-256: 6537a0ca9abd27799e415f56bee31297fc0c4023ec552667bc29942b0c59b7c2
font_01_sfnt_off0000efbc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEFBC 10572 bytes
SHA-256: b9bfdc40fb8d1897d92c9b93943575fd2c40962e95448629c13b8e722c6eb65e

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