Malicious PDF — malware analysis report

Static analysis result for SHA-256 f6a6d3c908a2717f…

MALICIOUS

PDF

84.9 KB Created: 2021-06-25 12:41:54 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: dad479a66b9328430516846dff4490ab SHA-1: e5961edd479983dce6c12910b1d602a932107d01 SHA-256: f6a6d3c908a2717f18de7a4e90714b7306f4e49995abdf0005946f116079ae94
96 Risk Score

Malware Insights

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

The PDF file contains numerous embedded URLs pointing to compromised WordPress sites, indicating a link farm or SEO manipulation tactic. The ML classifier strongly flagged this PDF as malicious, and heuristics identified it as a link farm on disposable hosting. While no scripts were extracted, the primary attack pattern involves directing users to external, potentially malicious, content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

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://cructi.ru/uplcv?utm_term=maths+tricky+quiz+questions+and+answers
    • https://adiwirawanbali.com/wp-content/plugins/super-forms/uploads/php/files/2642cc2b5e62d7db9578b6bcbe524eda/70646665629.pdf
    • http://falerisztika.hu/tmp/pibeziko.pdf
    • https://digidatadecolombia.com/wp-content/plugins/super-forms/uploads/php/files/95f7530fbf6e73da4b4d41504b3ccdc7/mosifewojibajisodegebuda.pdf
    • https://shopinhome.com/ci/userfiles/files/22053471170.pdf
    • http://guanzhuli.com/userfiles/file/xowepapifijiferebumap.pdf
    • http://getawaynewzealand.co.nz/wp-content/plugins/formcraft/file-upload/server/content/files/1609fde0234713---90145021108.pdf
    • http://www.adanakursmerkezi.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607ccddd26044---81770459857.pdf
    • https://xlux.vn/wp-content/plugins/super-forms/uploads/php/files/u69mbdcs66o519u43m0mo82v22/lareno.pdf
    • http://prattsofdouds.com/clients/d/d8/d85aab9f4bcbae69c8358f7a9990a0b1/File/47583401560.pdf
    • http://porpora.info/imagenes/imagenes_contenidos///sebidiv.pdf
    • http://thefutureofgolf.eu/wp-content/plugins/formcraft/file-upload/server/content/files/16070ef5014eee---89600839336.pdf
    • https://www.xcelsus.de/wp-content/plugins/formcraft/file-upload/server/content/files/160aa5f15b0d59---nozeg.pdf
    • https://izharfoster.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608f921d6c9f0---fabikikiw.pdf
    • http://xn--80akij1ajew.xn--p1ai/wp-content/plugins/formcraft/file-upload/server/content/files/160bc54d1bb3eb---93704110509.pdf
    • https://saftanton.dk/wp-content/plugins/formcraft/file-upload/server/content/files/160ae5ad7b11eb---64376158832.pdf
    • http://ever0036.com/assets/uploads/ckedit/files/20210528191223.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e4b2.bin
135a387944cdfeb82c7fcef9b043eedd8fcf5075f678a3b0fb897d5b9f60ff6c		 pdf-font-stream PDF embedded font (sfnt) at offset 0xE4B2 11012 bytes
font_01_sfnt_off0000fe39.bin
f4904495abe9614e8f35d299eb228e054994a5cf4ccbffef31fbc6a6af8f4d7e		 pdf-font-stream PDF embedded font (sfnt) at offset 0xFE39 17712 bytes
font_02_sfnt_off00012cf8.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1		 pdf-font-stream PDF embedded font (sfnt) at offset 0x12CF8 16792 bytes

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