Malicious PDF — malware analysis report

Static analysis result for SHA-256 a8f44e48e627f65f…

MALICIOUS

PDF

75.6 KB Created: 2021-04-17 14:30:11 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-21
MD5: 0359c2887b72d4c6c3b8b576fa9b3d8f SHA-1: 2f40d74d5ce6d0361b92248d8ab661a86c52e3a9 SHA-256: a8f44e48e627f65f5fd21503d46f5ef203110d164ab4f5af788d4728ecd2084c
134 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF file was flagged by ClamAV as Pdf.Phishing.Trojan and an ML classifier indicated a high probability of maliciousness. It contains an external URI pointing to a suspicious domain, 'nipisod.ru', which is also identified as a link farm on disposable hosting. While no scripts were explicitly extracted, the PDF structure and the presence of external links suggest an attempt to redirect the user to a malicious site, likely for phishing or to download a secondary payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9994

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://nipisod.ru/strik?utm_term=past+simple+verb+to+be+exercises+doc PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4404313/normal_5fe805e1d6c48.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4368742/normal_60627b92967ae.pdfIn PDF document text
    • http://tinesemexogo.mygamesonline.org/tetozukabu.pdfIn PDF document text
    • http://netekepipavosis.sportsontheweb.net/zagizorevewokagi.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4386076/normal_604d8076f2031.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4446776/normal_6046243894b6b.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4482426/normal_5fe7e8257aadf.pdfIn PDF document text
    • http://mebel-albero.ru/my_toshiba_tv_has_a_red_blinking_lightrfo5k.pdfIn PDF document text
    • http://e-devletodeme.net/61396426392u5o2t.pdfIn PDF document text
    • http://stroiline74.ru/627528914037tuyr.pdfIn PDF document text
    • http://vizenam.medianewsonline.com/best_magazine_design.pdfIn PDF document text
    • http://limons.space/28931577551qphl5.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://uploads.strikinglycdn.com/files/803f1bc8-90ae-4a82-b017-c8b726b4308b/defasogijam.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/24983610-61fd-4d43-8089-8ccbdb08e18b/is_real_national_income_the_same_as_gdp.pdfIn PDF document text
    • https://8e985b84-f336-4757-86d8-bf3f50c95819.filesusr.com/ugd/cac9e4_65567a4eab3645aba75346cbe241786e.pdf?index=trueIn PDF document text
    • https://3794eb9c-cc8b-492c-aecc-44533f76aaa6.filesusr.com/ugd/1ee69b_f317e7ec152b4d61b2ecbc220c95f4fd.pdf?index=trueIn PDF document text
    • https://a2876ee3-c470-454a-91e2-e108d831033a.filesusr.com/ugd/e8dba5_c38e97f4c11947e5be90ce3d4e9bcb3b.pdf?index=trueIn PDF document text
    • https://30c74dc1-c3f2-4e71-8253-1ec84f3b94e1.filesusr.com/ugd/b8c6fa_ff9940bef55240dbb2330831b1f71d13.pdf?index=trueIn PDF document text
    • https://14319df0-7947-4f0d-bbb3-eaa17d5eb23e.filesusr.com/ugd/c45f38_b0f6f68dd46d44efb43e6ace3d445295.pdf?index=trueIn PDF document text
    • https://bb74f61c-7045-47bf-9a7e-968101ee373e.filesusr.com/ugd/81ef4b_435bfd925f984d93939df0bc420188a9.pdf?index=trueIn PDF document text
    • https://df9240ce-57b4-430e-a582-521170ca5232.filesusr.com/ugd/10b03a_6f01cf601d2a46c0b346d1ab4cf1b1af.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/28c9ef4d-0635-4e03-a62c-0bae6ed2c8cc/82293653733.pdfIn PDF document text
    • 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
    • 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_off0000d561.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD561 5488 bytes
SHA-256: 5b9e9c37b23625fab848659dceab355bd232f05e11038731fb98e8cf90e69552
font_01_sfnt_off0000e7f3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE7F3 10484 bytes
SHA-256: 4d523957d1e9957300ec98db9b91fae178df6debaf48c11e4df65caabf88d838
font_02_sfnt_off00010bd0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10BD0 16060 bytes
SHA-256: df1d2c903cabdf2976887e260da0b25217edeb5ce2b71f315001024534e8e210

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