Malicious PDF — malware analysis report

Static analysis result for SHA-256 b21995f65e2e6c75…

MALICIOUS

PDF

79.5 KB Created: 2021-03-19 14:20:44 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-22
MD5: 7808008e264203655b8e891ac29cee4c SHA-1: 2909710aa7ddd026939b6a7cd115145f6a328de5 SHA-256: b21995f65e2e6c7502996b25981b75607accb9a10aa949e6e4c242845a3652a7
186 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains a large number of external links, as indicated by the PDF_SEO_LINK_FARM and PDF_SEO_DISPOSABLE_LINK_FARM heuristics. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or malware distribution. The embedded URLs point to potentially malicious domains, and the document body, though heavily obfuscated, contains metadata suggesting it was generated by wkhtmltopdf, a tool sometimes used to create malicious PDFs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9994

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://resalured.ru/strik?utm_term=jack+reacher+2+netflix+streaming+release+date PDF link annotation
    • http://idem-peshkom.ru/fake_gps_joystick_apk_2020a5pmv.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4454803/normal_5fe55c23cb42f.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4371814/normal_60500e954167d.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4404955/normal_6005279aa35fa.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4366316/normal_5fc9a3112678b.pdfIn PDF document text
    • http://plsale.pro/thinking_like_an_engineer_4th_edition6opv1.pdfIn PDF document text
    • http://mihetos.xyz/what_is_a_world_without_religion3264y.pdfIn PDF document text
    • http://help-copyrightviolationhelpcenter.com/172824852141tz70.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/c2307a1a-4ab5-4a23-acb4-f226cd6c016a/16812467683.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/70c12ffd-604c-45ba-a165-618e9954c612/jbl_lsr305p_mkii_review.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/7f7155b7-c3ba-41a5-b2c4-337c89fc6c28/bodufojej.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/304c03a8-4f55-4b4b-887e-8e1da46967d6/cartucce_originali_per_epson_wf_2630.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/735dbc4d-ed74-44fc-8b8b-e13121563d7b/back_scratch_test_strength.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/9947a863-a2e2-498d-918d-1d8b7689cd10/what_does_mental_stamina_mean.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/c7db6239-e2e4-4eea-afbd-4c83ce831217/30630929343.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/ba6b6a94-a4ec-407c-9598-36527d368000/what_is_operating_system_and_its_types.pdfIn PDF document text
    • https://58eafb2e-ea74-4523-a1b2-d2e0fe9bfe54.filesusr.com/ugd/466fa0_83aae9c5cca04b9daf2b92f89e0cbfa8.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/1841f96f-2363-4920-bdf0-74708aaa5950/panasonic_plasma_tv_wont_turn_on.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/a70ed0e0-6b35-455d-9ed1-a2b9fe111b17/36780322846.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/54401b29-fe2c-4157-8844-7a2d91020fb9/shepherding_the_flock_of_god.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/4d286215-26c1-47a4-a571-3e8aad2a13b6/dobevetamopagoru.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/47a5e5cf-2267-45bf-b214-99ba5974a0af/dr_dre_beats_commercial_song_2012.pdfIn PDF document text
    • https://8ac5c8e1-9174-427d-95c2-90bebb9f105a.filesusr.com/ugd/44b221_b282055588f24718b296e5264f13352e.pdf?index=trueIn 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_off0000f5fd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF5FD 5688 bytes
SHA-256: 6caefb86d803c132a33bda06973d2c1750d354e2f28f98b99cb3103d4e9c2122
font_01_sfnt_off00010935.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10935 11500 bytes
SHA-256: 9d86d7bfaf9f50ff6644a65b7e855975d9e3ad5450725fc1d700a47e2c142574

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