Malicious PDF — malware analysis report

Static analysis result for SHA-256 ed55d829a5b7c9e5…

MALICIOUS

PDF

85.0 KB Created: 2021-06-01 13:40:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-07-07
MD5: e38ecc90b72ff95c43d87bb1e3042a43 SHA-1: ba704f6614760b13d3e8de60c2bacfb615d7ea91 SHA-256: ed55d829a5b7c9e58d1b0ae4b82faffa21bbdd4fefac40f4324345c785bf0acc
186 Risk Score

Malware Insights

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

The PDF file contains numerous external links, identified as a link farm, with one prominent URL leading to a site offering 'english grammar worksheets'. This suggests a lure to drive traffic to potentially malicious sites. The ML classifier and ClamAV detection strongly indicate malicious intent, likely related to phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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 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://wastran.ru/pbw?utm_term=english+grammar+worksheets+for+grade+4+icse PDF link annotation
    • https://static.s123-cdn-static.com/uploads/4413573/normal_5feb201f63c31.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4407998/normal_5fd91cf9dcc88.pdfIn PDF document text
    • https://sidevobu.weebly.com/uploads/1/3/4/8/134866687/ragemitisov.pdfIn PDF document text
    • https://gebomatera.weebly.com/uploads/1/3/5/3/135396668/1384356.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4390995/normal_600ec20a44d82.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4486765/normal_6032f9b9ceb9e.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4425501/normal_600f4cf3b24b4.pdfIn PDF document text
    • https://ferafavobob.weebly.com/uploads/1/3/4/6/134671558/semutelewulovi.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4421983/normal_5fecaeca5a7cf.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4491665/normal_602413f660f20.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/1cf3c192-7d8b-4d5d-a86e-78042ec10cf2/besepokimir.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/4a95c1ab-32aa-4909-9430-192e853897f0/vitamix_a3500_or_750.pdfIn PDF document text
    • http://supatibu.pbworks.com/f/justinas_marcinkeviius_mindaugas.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/7cf78d50-de99-47fb-a520-8f68f02a903a/special_right_triangles_45-45-90_word_problems.pdfIn PDF document text
    • http://jesababa.pbworks.com/f/7368294766.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_off00010cdb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10CDB 5636 bytes
SHA-256: cf94f78629c4a8d386ee080e7df893df43bbe59870fab5e7d91c469bbedcee15
font_01_sfnt_off00011ffb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11FFB 11784 bytes
SHA-256: 8061aad5491edf7a817f76397a241f40d5fcfd69c8084d87e244e39b2ee64451

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