Malicious PDF — malware analysis report

Static analysis result for SHA-256 5d33db731c50e93c…

MALICIOUS

PDF

73.3 KB Created: 2021-04-24 17:41:55 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-13
MD5: 33f68fa0d933d4b9bf70126819771247 SHA-1: c97b74a605fb48a3bb6d01c7788012b0ae6bf74e SHA-256: 5d33db731c50e93c581bf779f9246b4124ff179a1a527945ec0e4b1194d06bd1
186 Risk Score

Malware Insights

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

This PDF file is identified as malicious by ML classifiers and ClamAV, indicating a phishing or trojan payload. It contains a large number of external links, many pointing to disposable domains, suggesting a link farm or redirection scheme to host malicious content. The document body, though heavily obfuscated, contains text related to 'worksheets' and the authoring application, likely a lure to disguise the malicious intent of directing users to external URLs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

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://midufefew.ru/strik?utm_term=3rd+class+english+worksheets+pdf PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4492871/normal_6058fb590a311.pdfIn PDF document text
    • http://timekitaparezu.iblogger.org/69565524023.pdfIn PDF document text
    • http://verification-help.business/721122511313jf85.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4385859/normal_5ffa086c0b2e9.pdfIn PDF document text
    • http://mazafaka69pussy.online/9780405566841zww.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4367013/normal_5fc6149b2afe2.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4487382/normal_606e60a8a8f6c.pdfIn PDF document text
    • http://bu-markett.com/1361775894241jkr.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4413347/normal_604982e5a3de4.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4489404/normal_5fe14b1c48b54.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4410731/normal_603442ef1d668.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4371265/normal_5fca864e4c167.pdfIn PDF document text
    • http://joxexezukefu.22web.org/why_does_my_directv_remote_not_change_channels.pdfIn PDF document text
    • http://xabibumat.iblogger.org/rocket_league_cross_platform_xbox_one_ps4.pdfIn PDF document text
    • http://extraevents.ru/a_street_cat_named_bob_book_age_ratingwjn5z.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4426280/normal_5ffe622a2ea89.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4480736/normal_605fa1401138f.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4462056/normal_600d66ed75c74.pdfIn PDF document text
    • http://maleev.online/kindle_fire_hd_7_4th_generation_case_ukybr29.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://2f8a6ab9-e864-4757-b083-6627a13f4c48.filesusr.com/ugd/405339_36719cce8efb467a8cb65b2de0dea9c8.pdf?index=trueIn PDF document text
    • https://c03439ef-6557-4199-865e-586791a52b6c.filesusr.com/ugd/6bb4a2_67a2eecf9b28410c840c2b2d66643c0f.pdf?index=trueIn PDF document text
    • https://cf587a47-7c2f-4f55-8bbb-21a4c73503f7.filesusr.com/ugd/8ea597_7481b8ac8ae04ebcb37ad7a97c3a38d3.pdf?index=trueIn PDF document text
    • https://b2d1eea7-aef5-47fc-962c-88b5513ecafc.filesusr.com/ugd/3a57bc_b95ab88a766f487c9e830fac8fb6b2b5.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_off0000de54.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDE54 5644 bytes
SHA-256: bfe76d468a5aad30698e4a0f8048fb437d0f68594c2cda31a6231cbba925d11f
font_01_sfnt_off0000f191.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF191 11208 bytes
SHA-256: a6c0b964ee09841bd33f1115063fe3241bf6d9aec198d0e8bdf5acb06871ef73