Malicious PDF — malware analysis report

Static analysis result for SHA-256 85fba69d4ba736d1…

MALICIOUS

PDF

72.2 KB Created: 2021-07-26 23:35:10 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 22b18f7d10211cb37d387ba2d7914f25 SHA-1: 481bf429a7c94ba94e8da40ba91a569df1286707 SHA-256: 85fba69d4ba736d12d1deab04f00dc3c5904874fb7efc36c61a281ecc375b258
96 Risk Score

Malware Insights

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

The PDF file contains a large number of external links, many of which point to compromised WordPress sites. The ML classifier strongly indicated maliciousness, and the link farm structure suggests an attempt to manipulate search engine results or redirect users to potentially harmful content. No scripts were extracted, and the document body was unreadable binary data.

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 http://hk-dcc.com/wp-content/plugins/super-forms/uploads/php/files/a28efp4ssq7afvglrmvcsdfp99/lurifutububuwefunirubi.pdf In PDF document text
    • http://dxczx.com/ckfinder/userfiles/files/20210717_091755.pdfIn PDF document text
    • https://artbynela.com/uploads/file/40216327020.pdfIn PDF document text
    • https://allianceflooring.net/wp-content/plugins/super-forms/uploads/php/files/5effd852cc81ade36dd7cb471978495a/69984905049.pdfIn PDF document text
    • http://thunderstar.cn/userfiles/file/20210702034912258887640.pdfIn PDF document text
    • http://limpiasol.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606f9bf79ee57---34515703907.pdfIn PDF document text
    • http://careerhack.net/wp-content/plugins/formcraft/file-upload/server/content/files/1606c97d8dc8f6---68038335573.pdfIn PDF document text
    • http://famcareconnect.org/wp-content/plugins/formcraft/file-upload/server/content/files/160a8e5a885998---35252150671.pdfIn PDF document text
    • https://boldvision.tv/wp-content/plugins/formcraft/file-upload/server/content/files/16090d408b4141---84966954679.pdfIn PDF document text
    • http://alsumiri.net/wp-content/plugins/super-forms/uploads/php/files/ee7810e6a58ea886315a17a5dcc2f9e5/26323551933.pdfIn PDF document text
    • https://www.ergunaygoren.com/wp-content/plugins/formcraft/file-upload/server/content/files/16082e7a9caf20---sepajeberi.pdfIn PDF document text
    • https://www.isgs.org/wp-content/plugins/super-forms/uploads/php/files/02b5513f49044a11a09829868a5421ce/nabukirefepezabitef.pdfIn PDF document text
    • http://hrudolf.com/userfiles/17058602721.pdfIn PDF document text
    • http://www.deep2001.com/images/library/File/dobifupubuxa.pdfIn PDF document text
    • https://hkbca.org/UploadFiles/file/20210624052532124.pdfIn PDF document text
    • https://shreenathtechnologies.com/userfiles/file/47579010565.pdfIn PDF document text
    • http://bycongroup.com/UserFiles/file/52602740630.pdfIn PDF document text
    • http://www.mueblesgamez.com/ckfinder/userfiles/files/25994989669.pdfIn PDF document text
    • https://torrentclub.vip/wp-content/plugins/super-forms/uploads/php/files/fko7bhi173hfbo65h6ua3nnp9t/15276751851.pdfIn PDF document text
    • http://ck-tct.ru/userfiles/file/80655089281.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/PmAiG5ZyT-k/uplcv?utm_term=fundamentos+de+enfermer%C3%ADa+susana+rosales+barrera+eva+reyes+g%C3%B3mezPDF 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_off0000b531.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB531 16152 bytes
SHA-256: 21e0c6db8dc5f55723de9ee4eefb20601cee370d048ac2c3acb9ffdc95f8c355
font_01_sfnt_off0000ddd5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDDD5 11264 bytes
SHA-256: d6dc6b4834da1fcda4d46dbc9d1b2866243297dab7ea647bcee88a0063e5c51e
font_02_sfnt_off0000f7d6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF7D6 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1