Malicious PDF — malware analysis report

Static analysis result for SHA-256 b9fc843c7b3e8c9e…

MALICIOUS

PDF

76.8 KB Created: 2021-06-20 18:24:45 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 3a8792aa6e67839147f99ca0334388ff SHA-1: 691135486845765aaaa3dab53f84883810c16b51 SHA-256: b9fc843c7b3e8c9ea62f34397e28a431e3dca1530ca43d388c2f8f79ee8e57b1
154 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous links, many pointing to compromised WordPress upload directories, suggesting a link farm designed to distribute further malicious content. The ClamAV detection and ML classifier strongly indicate malicious intent, likely phishing or malware distribution. The presence of multiple unknown URLs and compromised CMS upload links are the primary indicators of compromise.

Machine Learning

  • Nyx PDF Classifier malicious score 0.8924

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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
  • 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://bcbc3399.com/upload/files/gufuk.pdf
    • https://centar-znr-zop.hr/wp-content/plugins/formcraft/file-upload/server/content/files/16083ba5330e3d---niduzudaxogogegarabom.pdf
    • http://anhuicrew.com/upload_fck/file/2021-5-16/20210516121642843975.pdf
    • http://aeskulap24h.de/wp-content/plugins/formcraft/file-upload/server/content/files/160821ca006b3d---66365688427.pdf
    • http://villaturri.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609ceeee7c987---49757819050.pdf
    • https://atlanthealth.com/wp-content/plugins/super-forms/uploads/php/files/52391dea078152f27e2c12b19a44e690/wanijexaxijevasetukegub.pdf
    • https://alllegaltask.com/wp-content/plugins/super-forms/uploads/php/files/vi52r8nmkd6vos5s41mll6pek7/bofoxodogibamez.pdf
    • http://baigeleather.com/userfiles/file/regizux.pdf
    • http://kaplanpm.com/wp-content/plugins/formcraft/file-upload/server/content/files/16082de6d3a1b8---53165837577.pdf
    • https://tlpnw.com/wp-content/plugins/super-forms/uploads/php/files/79f64671d4dbed66d300b7bf56e9f750/kezuvewa.pdf
    • http://busankid.com/webfiles/board/file/%5C/75623498312.pdf
    • https://www.pfgpartners.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/16094318f47e13---48006419410.pdf
    • http://unipell.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16083f3224c3d6---rusudafuzoranonedujimovep.pdf
    • http://www.drop-lok.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607dbe20274e4---xuzuzutinazojibozeronul.pdf
    • https://www.burit.net/wp-content/plugins/formcraft/file-upload/server/content/files/16079835320e00---42028413397.pdf
    • http://www.birapart.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b806b1a9c4f---23399070120.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://feedproxy.google.com/~r/Uplcv/~3/1KS0DP0cxss/uplcv?utm_term=pokemon+gen+3+rom+hacks
    • https://sharpspringwww.kinsta.cloud/wp-content/plugins/super-forms/uploads/php/files/935e1d86524725e5757b9b98f1f27233/70027609422.pdf
    • http://scripts.sil.org/OFL

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00011053.bin
3a6bff0f33a861cb0e72905edf1a486d2d380c03af1e2b8a8edbce046ddb978b		 pdf-font-stream PDF embedded font (sfnt) at offset 0x11053 5408 bytes

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