Malicious PDF — malware analysis report

Static analysis result for SHA-256 664ca9f90c1a07c8…

MALICIOUS

PDF

78.2 KB Created: 2021-05-21 21:40:15 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-07-07
MD5: e0b0d127376e4663f7072be05416171a SHA-1: 145ff0a2d463327aca4ec8bcd3365ca7803f921c SHA-256: 664ca9f90c1a07c8e47226576988c9f5c7229235c7c82e5d7ab5131f44fa9e67
186 Risk Score

Malware Insights

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

The PDF file contains a large number of external links, many hosted on disposable domains, suggesting a link farm or phishing operation. The ML classifier and ClamAV detection strongly indicate maliciousness. The document body, though heavily obfuscated, appears to be a lure related to educational content, likely to trick users into clicking malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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.
  • 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 https://zajinet.ru/strik?utm_term=sintagma+nominal+ejercicios+resueltos+2+eso PDF link annotation
    • https://jadotonevuwupu.weebly.com/uploads/1/3/1/4/131407011/zaginekizilisatom.pdfIn PDF document text
    • https://nutikatike.weebly.com/uploads/1/3/4/6/134601603/4572b0c.pdfIn PDF document text
    • https://vatosulutat.weebly.com/uploads/1/3/4/5/134587817/ketekatanabed.pdfIn PDF document text
    • https://jerupixudenaxi.weebly.com/uploads/1/3/1/4/131437293/7edde.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4365536/normal_5fd38fa4cdde1.pdfIn PDF document text
    • https://sezunugavekavo.weebly.com/uploads/1/3/5/3/135321765/tekafegekin-bewotemoduje.pdfIn PDF document text
    • https://tenipimip.weebly.com/uploads/1/3/4/0/134042327/rerajide-luwobuvibuje-bozaladoluniki.pdfIn PDF document text
    • https://guxafosiwu.weebly.com/uploads/1/3/1/4/131453681/vuran.pdfIn PDF document text
    • https://vejamepune.weebly.com/uploads/1/3/0/7/130776484/xefexoborudu_kevoga_wabow_kisena.pdfIn PDF document text
    • https://rusipamisu.weebly.com/uploads/1/3/4/0/134017355/wufubowofigapod.pdfIn PDF document text
    • https://nozirurabi.weebly.com/uploads/1/3/0/7/130738896/7044865.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4412396/normal_601543d0af1de.pdfIn PDF document text
    • https://pobanuruwogijo.weebly.com/uploads/1/3/4/8/134882751/8414293.pdfIn PDF document text
    • https://giligigava.weebly.com/uploads/1/3/4/4/134494785/juzotox.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/c04affd6-1bbc-487e-a61c-0c8c7a896728/how_do_i_fix_my_nextbook_tablet_that_wont_charge.pdfIn PDF document text
    • https://s3.amazonaws.com/kozewuposoridil/jokuzuwomofase.pdfIn PDF document text
    • https://s3.amazonaws.com/xakapudakadu/himno_al_maestro_honduras_letra.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/e1308e7e-d16c-46ef-be4a-d432857099b6/fozuvuperere.pdfIn PDF document text
    • https://s3.amazonaws.com/wefadep/kenituxubab.pdfIn PDF document text
    • https://s3.amazonaws.com/bubeto/59113734960.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

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f0ea.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF0EA 5428 bytes
SHA-256: 05bc314d3d9990035288bc0ebbea0a5397f91b3ec9d16a0f9124e15924656153
font_01_sfnt_off0001034f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1034F 11908 bytes
SHA-256: b8a9df3b6fe52fdb0d75cf84726cdfbf3d9686297904297629c4a93149e16e58

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