Malicious PDF — malware analysis report

Static analysis result for SHA-256 c43cf692f70cacc0…

MALICIOUS

PDF

79.3 KB Created: 2021-09-02 02:34:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 71bcf36ac8236140c77282cb0802fa05 SHA-1: 1e7a201bef93237786ce16bfa3cd458803f0cbfd SHA-256: c43cf692f70cacc06029a9df9e938d2b8491a29f806b5e347f10e0b981e1d6e1
116 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 User Execution: Malicious File

The sample is a PDF document that contains a link farm pointing to multiple PDF files hosted on compromised WordPress sites. The ML classifier strongly indicates maliciousness, and the heuristic firings suggest a callback phishing or tech-support scam pattern. The document body is heavily obfuscated, preventing a clear understanding of its specific lure, but the presence of numerous links to potentially malicious PDFs indicates an attempt to redirect users to harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9978

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.
  • Callback phishing phone lure medium SE_CALLBACK_LURE
    Document asks the user to call a phone number in billing, refund, subscription, fraud, or security context — consistent with callback phishing or tech-support scam patterns. Suppressed for legitimate-issuer (IRS/gov/official-form) documents that carry no urgency or charge/dispute escalation.
  • 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://duonglaohanoi.com/userfiles/file/jotujasazijelogizowalalik.pdf In PDF document text
    • https://celovechurch.org/wp-content/plugins/super-forms/uploads/php/files/b1433cff43704ba76aa90701678c05bc/rujawoninimuwajoreg.pdfIn PDF document text
    • https://www.icslights.com/wp-content/plugins/super-forms/uploads/php/files/aa706d99623a92455b5815ad99c7529a/79800185565.pdfIn PDF document text
    • http://unicorn-furnitures.com/d/files/tosuxawamikowenofirebato.pdfIn PDF document text
    • https://phoenixknights.co.uk/wp-content/plugins/super-forms/uploads/php/files/b9463e6d9604a2909911bb37ca7a6b86/xunevirawuwawegonu.pdfIn PDF document text
    • https://inncredel.com/uploads/xejesifonevoner.pdfIn PDF document text
    • https://adlinefor.com/home/webagen/public_html/korn/data/file/duwug.pdfIn PDF document text
    • https://fjordancv.info/wp-content/plugins/super-forms/uploads/php/files/431935942d885d2f4ad114738a5d1864/63749126571.pdfIn PDF document text
    • http://nature-revive.org/files/file/77675003267.pdfIn PDF document text
    • http://gaytonfa.com/upload/files/jegireneta.pdfIn PDF document text
    • https://www.pietri-automobiles.com/wp-content/plugins/super-forms/uploads/php/files/idpf77rg4r20manqhupjosbjn7/dunilibasadelapilimofujol.pdfIn PDF document text
    • http://bisenzia.it/userfiles/files/88964894025.pdfIn PDF document text
    • https://maintogelonline2.com/contents/files/tizajupejuvasox.pdfIn PDF document text
    • http://sushiloverca.com/uploads/files/doliwajuzid.pdfIn PDF document text
    • https://www.wflorlando.com/wp-content/plugins/super-forms/uploads/php/files/c94c08dc0c9142de138e464c4ff18dc8/15345746636.pdfIn PDF document text
    • http://thuaphatlailongthanh.com/upload/contentFile/minhchau/file/xijeripabamekobokomad.pdfIn PDF document text
    • https://sporyolu.com/resimler/files/78227751578.pdfIn PDF document text
    • https://lllk.ru/wp-content/plugins/super-forms/uploads/php/files/b2c677060fe90ddd0ca0c851219821bf/29835233182.pdfIn PDF document text
    • http://www.petersmetalstitching.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/160dff0f89b650---towabujarosagozitusokopa.pdfIn PDF document text
    • https://directprocessors.com/wp-content/plugins/formcraft/file-upload/server/content/files/16096c7cf67f98---xuvokat.pdfIn PDF document text
    • https://namratalakhotia.com/userfiles/files/97501172387.pdfIn PDF document text
    • https://comodee.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608133fc07db8---nibuvov.pdfIn PDF document text
    • https://almuhja.net/ckfinder/userfiles/files/kikofogonok.pdfIn PDF document text
    • https://groupunsur2.com/contents//files/pekufezawesexuvodijas.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/1KS0DP0cxss/uplcv?utm_term=product+line+upPDF 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_off0000d698.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD698 16048 bytes
SHA-256: 00f4bb22ae377f9109b2dffaa552ff4dfb3c1beb1a03c6c90d00f1f12b77ba2a
font_01_sfnt_off0000ff58.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFF58 10280 bytes
SHA-256: d12fe72adc91638c9ed2d00477445c63f19cbdd5130f399f067f916deeafef39
font_02_sfnt_off00011685.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11685 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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