Malicious PDF — malware analysis report

Static analysis result for SHA-256 5b2ca1e609eb84bb…

MALICIOUS

PDF

72.9 KB Created: 2021-06-09 23:11:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-13
MD5: 8692f0249c264628fc5b469ba9300e8b SHA-1: 04f6d812552b5d6d4047930803858351110200d1 SHA-256: 5b2ca1e609eb84bbe541c03021659978c8d5a4919be78b9e807b9d57c7239298
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 pointing to disposable hosting, and is flagged by ML classifiers and ClamAV as malicious. The document body, though heavily obfuscated, suggests a lure related to 'correcting grammar worksheets'. The presence of numerous external links indicates a link farm or phishing attempt, likely using spearphishing as the initial access vector.

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://medvor.ru/pbw?utm_term=correcting+grammar+worksheets PDF link annotation
    • https://static.s123-cdn-static.com/uploads/4422133/normal_5fca4a548a1f3.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4449177/normal_6006e5a7322bd.pdfIn PDF document text
    • https://xigijoxupawise.weebly.com/uploads/1/3/3/9/133999412/kezazivivijipar.pdfIn PDF document text
    • https://latafazogon.weebly.com/uploads/1/3/4/7/134728758/ninen_rifage_vekitineritiwip_xixegixod.pdfIn PDF document text
    • https://tumurotijom.weebly.com/uploads/1/3/4/5/134512141/3562848.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4470211/normal_606e842bb6bab.pdfIn PDF document text
    • https://peziwotikiju.weebly.com/uploads/1/3/4/6/134602895/22a265b90062df.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4472506/normal_605b02aadbe9d.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4477638/normal_600a4bea5e4a8.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://finatin.pbworks.com/f/22774641122.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/85ddc005-9980-4c28-a9b4-00936a53d023/67289450725.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/938d26dc-dca6-44f7-a914-7fa8b4db43ec/musivemi.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/3adab943-469a-497c-a596-ca97b8cbe8e5/95368770246.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/c06b6fd8-f80a-41da-bfb1-9be9054ea093/xivaserogerewupe.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/72b1cd6e-b46d-465a-9f93-e0190825859e/fefidotup.pdfIn PDF document text
    • http://zulamiz.pbworks.com/f/supusaki.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/a3438ce5-7f24-4847-a151-19adeee2e346/instal_coreldraw_2020.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/e50d3716-82c3-4a55-8f82-f29430ff2d1c/63559356467.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/0597479c-eb90-4d5f-be41-f1c2cf9ac23b/why_wont_my_hp_officejet_4620_print_black.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_off0000e1d3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE1D3 5244 bytes
SHA-256: 30483371d7d52d4d67b916137e2ec24dc73d3c0618e45ae09770180da3730d19
font_01_sfnt_off0000f38f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF38F 10320 bytes
SHA-256: d5a68a7d5b70820480da71556fd6e802d77735814059f26cc0c18c72a1aff85b