Malicious PDF — malware analysis report

Static analysis result for SHA-256 51bffc5dd1a5fb43…

MALICIOUS

PDF

124.0 KB Created: 2021-04-06 11:37:37 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 92ec8256f14624b0d5fda40e069a5d86 SHA-1: dc96dcf18edfdb69ebb0c44aa7f2c31c3ecc5b79 SHA-256: 51bffc5dd1a5fb43730c3c3ec13934664cb2ee917071166898a657dea149b39b
156 Risk Score

Malware Insights

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

The PDF contains a large number of external links, many of which are SEO-optimized and point to other PDF documents, suggesting a link farm designed to drive traffic or distribute malicious content. The ClamAV detection and ML classifier strongly indicate malicious intent, likely related to phishing or malware distribution via these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://zajinet.ru/award?keyword=cxc+biology+past+papers+multiple+choice+pdf
    • https://cdn-cms.f-static.net/uploads/4470014/normal_606c1b5348059.pdf
    • https://ragenakesigufu.weebly.com/uploads/1/3/2/7/132740294/3408622.pdf
    • https://tunugezujemis.weebly.com/uploads/1/3/4/3/134307821/wirexoguwimi-bikasofiresovi-fisoz-kupikikaru.pdf
    • http://rabevazilogu.iblogger.org/bewuvowudowe.pdf
    • https://static.s123-cdn-static.com/uploads/4366366/normal_6000237490a8c.pdf
    • https://cdn-cms.f-static.net/uploads/4486374/normal_606782e237cd2.pdf
    • https://cdn-cms.f-static.net/uploads/4495244/normal_5fd61b9bbbf35.pdf
    • https://cdn-cms.f-static.net/uploads/4408335/normal_602aec741e6c8.pdf
    • https://cdn-cms.f-static.net/uploads/4496216/normal_6068b9adb7855.pdf
    • https://static.s123-cdn-static.com/uploads/4368228/normal_600473f927a34.pdf
    • http://gexopuvarubuje.iblogger.org/fundamentals_of_css.pdf
    • https://gidedumewulo.weebly.com/uploads/1/3/5/9/135961218/dunamali_dokomoduripise_bepivow.pdf
    • https://cdn-cms.f-static.net/uploads/4413697/normal_6056faa2b12d0.pdf
    • https://cdn-cms.f-static.net/uploads/4413362/normal_605a564a34f4e.pdf
    • http://sekekejawewonul.iblogger.org/beginning_consonant_blends.pdf
    • https://cdn-cms.f-static.net/uploads/4415526/normal_603a5cf496e81.pdf
    • https://kigolaris.weebly.com/uploads/1/3/1/3/131380971/4549631.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://b46c4cda-4951-41c0-816f-bbf02eee4d9b.filesusr.com/ugd/4ff992_8d9563bd6d674a47886585ebe01f2414.pdf?index=true
    • https://uploads.strikinglycdn.com/files/17d6841e-8b18-45ec-b2df-d6a64a7687fb/58610035670.pdf
    • https://6cdb29d4-22ce-4aaf-9e51-562b59d50851.filesusr.com/ugd/1b20fb_d2807c04ee134b82b9ceb680d2fc5469.pdf?index=true
    • https://4fe85328-8dbf-40e9-afa8-2c8d6ff8a9c8.filesusr.com/ugd/9c0842_13a42a8233bc442188619c0ca0e199ca.pdf?index=true
    • https://uploads.strikinglycdn.com/files/ed46351d-6a9e-4171-81e8-518b0f706f87/tardis_plans_full_size.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://scripts.sil.org/OFL

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0001a6ce.bin
300c6ec8d612eec7422330382c975ec2de1250987511b4ba9b8093ba1bc0e9d5		 pdf-font-stream PDF embedded font (sfnt) at offset 0x1A6CE 5784 bytes
font_01_sfnt_off0001ba5d.bin
3ce2668e95620fa0cfd488c63bb9a25cc829460bb5fd99e60d8c1aab97b802d7		 pdf-font-stream PDF embedded font (sfnt) at offset 0x1BA5D 12496 bytes

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