Malicious PDF — malware analysis report

Static analysis result for SHA-256 e7cfbfd5e7771bfe…

MALICIOUS

PDF

82.3 KB Created: 2021-04-07 06:56:49 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: ad602e1f78c1ba3261b591167d196f5f SHA-1: 3fcb63f0657f9b4e239e55f7ed336060399674a2 SHA-256: e7cfbfd5e7771bfeacac8afdbb3d1b968ee112778e5d529eb9c62447d3335c57
156 Risk Score

Malware Insights

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

This PDF file was flagged by ClamAV as a phishing trojan and a machine learning classifier indicated a high probability of maliciousness. It contains numerous external links, many pointing to PDF files hosted on various platforms, suggesting a link farm or distribution network. The document body, though heavily obfuscated, contains text related to 'Nejm author submission guidelines' and 'wkhtmltopdf', likely a lure to disguise the malicious intent of directing users to potentially harmful external sites.

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://dafemum.ru/123?utm_term=nejm+author+submission+guidelines
    • https://xunujilitaga.weebly.com/uploads/1/3/5/3/135315779/bidebejunok.pdf
    • https://cdn-cms.f-static.net/uploads/4485176/normal_6037b92088efa.pdf
    • https://cdn.sqhk.co/merabuvi/gjibjhi/biwifumuf.pdf
    • https://cdn-cms.f-static.net/uploads/4470385/normal_601dca9b089a6.pdf
    • https://cdn.sqhk.co/pujimuxuja/sigiha5/nufezukotisowejojexugotur.pdf
    • https://zudibuliri.weebly.com/uploads/1/3/5/3/135319562/0caf745181df.pdf
    • https://cdn.sqhk.co/rozesivotix/JgfEIe5/tip_top_nails_menu.pdf
    • https://kopujigok.weebly.com/uploads/1/3/4/8/134862339/9500827.pdf
    • http://kuvenumine.mygamesonline.org/how_do_you_pair_jbl_free_wireless_earbuds.pdf
    • https://bolojowugupi.weebly.com/uploads/1/3/4/8/134886087/wozuguxovaxexupemaxa.pdf
    • https://cdn-cms.f-static.net/uploads/4490116/normal_606bf64eb9678.pdf
    • https://cdn-cms.f-static.net/uploads/4486035/normal_6028c0e300faa.pdf
    • http://bokaxakoz.sportsontheweb.net/3726653930.pdf
    • https://cdn.sqhk.co/jufebarur/EOVjhjb/nupifexisazuzu.pdf
    • https://static.s123-cdn-static.com/uploads/4446162/normal_5fe28a5ce8a56.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://436240a4-ef10-404e-ad90-c5cab949c7af.filesusr.com/ugd/3fb742_3b297da27e594e1db4e035fd351c2372.pdf?index=true
    • http://timerojulawu.myartsonline.com/56968607235.pdf
    • https://5a995288-ce6f-4ae3-a3e6-14272d8003db.filesusr.com/ugd/7be1cd_810e25f97ee541788b9d6a56e12ea51d.pdf?index=true
    • 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_off000103c8.bin
d86b88544a2b5af08c8712e7447bd79e7468b5db8ebf43c2e38585a43e3aefcf		 pdf-font-stream PDF embedded font (sfnt) at offset 0x103C8 5424 bytes
font_01_sfnt_off00011613.bin
fa85087290d2aacf29d418fe2281dc256d1f93d05a17b04432de13b9fb2716ed		 pdf-font-stream PDF embedded font (sfnt) at offset 0x11613 11040 bytes

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