Malicious PDF — malware analysis report

Static analysis result for SHA-256 b767c555af40d6df…

MALICIOUS

PDF

78.6 KB Created: 2021-04-08 21:27:17 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 36e46d8d16cb50af9ed58cdd6cb8185f SHA-1: 205e40dfbde21f6d82eb880a746f4b445b0d3da9 SHA-256: b767c555af40d6df8ffa35552ee8ddf3d9ba720fae352682f556bf8fa27db215
186 Risk Score

Malware Insights

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

The PDF document contains a large number of embedded links, masquerading as CDC instructions on mask-wearing, to various external websites. This behavior is indicative of a link farm or phishing lure designed to redirect users to potentially malicious content. The ML classifier and ClamAV detection strongly support its malicious nature.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9994

Heuristics 6

  • 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.
  • 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 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://ponafet.ru/strik?utm_term=cdc+instructions+on+how+to+wear+a+face+mask
    • https://bajomunimiru.weebly.com/uploads/1/3/1/0/131070213/kolokinuvokila-vikozul.pdf
    • http://nitapida.mywebcommunity.org/ged_science_practice_test_free_printable.pdf
    • https://revabusabozuvum.weebly.com/uploads/1/3/5/3/135398016/9d2ba3dcad220c.pdf
    • http://sozimaxetupow.mywebcommunity.org/astral_cpvc_pipes_price_list_2020.pdf
    • http://jakazobik.iblogger.org/sokowur.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://b47237a6-1880-4d87-9598-f01162bab054.filesusr.com/ugd/1fe0ea_b238227c28b546eb9da1ad073d4ad6dc.pdf?index=true
    • https://d67926d6-99fe-48a4-938f-95006fdf2de6.filesusr.com/ugd/21d82e_fad68ff92dc04716b8cd56bc2050ac58.pdf?index=true
    • https://d99d9bf7-a5e0-49f2-90ac-0d1bc881463d.filesusr.com/ugd/0182ef_89b9cd5ac33c4dc8ad7b97c07fce37aa.pdf?index=true
    • http://zenakezogutomu.onlinewebshop.net/slimming_world_free_foods_list_2020.pdf
    • https://8459f3b7-b2e6-4b58-af31-5f29adf293b7.filesusr.com/ugd/a68450_765de8db6e45455b9523b37fb5f05c21.pdf?index=true
    • https://31c8a3d4-0132-49f1-a04f-09c79d03e01f.filesusr.com/ugd/a4da84_2c26b5fb37bc44b4a88f08fa0ae4c26d.pdf?index=true
    • https://f7b0ef4b-317e-4f07-901b-4de91a029b50.filesusr.com/ugd/50f142_bdc6279704674e55b93a7377039a512b.pdf?index=true
    • https://101c3d73-5e22-4da1-a203-a3a2a794ce88.filesusr.com/ugd/69a512_dcf8a7a5637e47aa905a2ce0e0b0af78.pdf?index=true
    • http://kapetevik.epizy.com/browser_for_android_2._3._6_apk.pdf
    • https://fa5d8e44-005d-4c05-925d-ba60cb7f5023.filesusr.com/ugd/121e37_7ac2c74b69fb4c9bba5918d09def6062.pdf?index=true
    • https://b1e6e3cd-24a2-426a-8b7d-e8f4bd81915b.filesusr.com/ugd/83e584_2498204ce81141929403954980f4ad24.pdf?index=true
    • http://nafaradevofipaf.myartsonline.com/oci_application_form_uk.pdf
    • https://b6f97e74-198a-461d-a312-d71b9712332b.filesusr.com/ugd/a2d007_e180325b1aec4ca8a993370a66f8a560.pdf?index=true
    • http://mozabufapimil.epizy.com/74292181291.pdf
    • https://2d2b1dae-c014-4902-97e6-c3f1d56915cd.filesusr.com/ugd/70e5f7_76b8bc4422184ddd804c7eaa69faee39.pdf?index=true
    • https://6525eaf8-9a42-4119-9fb4-c3d475b3b78e.filesusr.com/ugd/80bfa9_2835efb7ef564ad7a06e9722fc27635b.pdf?index=true
    • https://4f0754e2-f0c4-47db-826b-83042027646c.filesusr.com/ugd/7a11b0_1bf8dc2052af43ecbe97fb382472875e.pdf?index=true
    • https://f270a619-8d23-4dc9-95fa-a4320df4b75e.filesusr.com/ugd/7bd364_ac6b605479fc46f48c7ed8e3d2e7fa92.pdf?index=true
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://scripts.sil.org/OFL

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f6a4.bin
0d1b81fde524b617061d9d7da525b925ec0fc8e21eafd0255fb24900add288af		 pdf-font-stream PDF embedded font (sfnt) at offset 0xF6A4 5288 bytes
font_01_sfnt_off00010889.bin
624cb85fa0a84c76bad487084ae59715d52b7fe89aaf5c5dff444d773c442fe9		 pdf-font-stream PDF embedded font (sfnt) at offset 0x10889 10612 bytes

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