Malicious PDF — malware analysis report

Static analysis result for SHA-256 b0b38a81d3c9147d…

MALICIOUS

PDF

80.5 KB Created: 2021-04-26 04:24:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 9d9ca5020864670a8167fc3bf46db40b SHA-1: 517afedc369d7c9f9135f32c3683819dbb862241 SHA-256: b0b38a81d3c9147d559bafb670878ab8057218ae23b93778d360ee99290dd717
186 Risk Score

Malware Insights

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

This PDF file was flagged by multiple heuristics as a link farm containing a large number of external links to other PDFs hosted on disposable domains. The ML classifier and ClamAV also identified it as malicious. The document body is heavily obfuscated and appears to be junk data, suggesting the primary purpose is to redirect users to potentially malicious content via the embedded URLs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

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-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://zajinet.ru/strik?utm_term=what+is+an+example+of+a+keto+breakfast
    • http://hrushch.space/bubble_witch_saga_3_free_download_for_androidwxh96.pdf
    • http://hugertely.xyz/swtor_legacy_guidek3d14.pdf
    • https://varusotefus.weebly.com/uploads/1/3/1/3/131398431/9a5be2.pdf
    • http://tokio-2020.fun/wosomop93f81.pdf
    • https://zupakikaxabu.weebly.com/uploads/1/3/1/3/131380404/pejilejuw.pdf
    • https://bupefozatige.weebly.com/uploads/1/3/4/3/134384552/4812519.pdf
    • http://bigtittybella.com/building_information_modeling_bim_extraction_software_market0wyqx.pdf
    • https://zomurudol.weebly.com/uploads/1/3/4/4/134492975/afe3cd7c91fd89.pdf
    • https://bisigategisabuv.weebly.com/uploads/1/3/4/8/134884720/radawowidurusa.pdf
    • http://phtech.site/download_oracle_virtualbox_for_windows_server_2012_r2qdbhu.pdf
    • https://binazinir.weebly.com/uploads/1/3/4/1/134108718/779436.pdf
    • http://microbladingcertificationdfw.org/fofirunsw9iw.pdf
    • http://se-mrush.com/frys_first_100_sight_words_flash_cardsr1fy1.pdf
    • http://hermidkovo.info/humminbird_fish_finder_sensornf0bx.pdf
    • https://butilitari.weebly.com/uploads/1/3/3/9/133997497/zuzizewip.pdf
    • http://tgesheff.xyz/359643189288fo4b.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://uploads.strikinglycdn.com/files/584fc136-5931-46fe-8528-d548973da642/55680221075.pdf
    • https://uploads.strikinglycdn.com/files/bb1b481c-a94c-4b69-8ba9-1bd834c0ab84/2011_chevy_traverse_radio_display_not_working.pdf
    • https://uploads.strikinglycdn.com/files/4dae8da6-4456-4872-b896-08486925c4ed/will_to_power_friedrich_nietzsche.pdf
    • https://uploads.strikinglycdn.com/files/621c37fc-72f5-4b1f-9d6d-76960c30a69a/61375422453.pdf
    • https://uploads.strikinglycdn.com/files/a7f3f690-e1fb-45f8-a163-e363174dd947/visual_basic_6.0_coding_tutorial.pdf
    • 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
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e8ee.bin
5c8db4037dd4a64d0cb511ebdde6cf3a7c881331b4b413982b0ce796e96db2c4		 pdf-font-stream PDF embedded font (sfnt) at offset 0xE8EE 5424 bytes
font_01_sfnt_off0000fb47.bin
63c70e39f94e8c1c2401e1127142acd7352ce3c9b5593a1280804bd160c754c9		 pdf-font-stream PDF embedded font (sfnt) at offset 0xFB47 10640 bytes
font_02_sfnt_off00011f9d.bin
292b67320f20e7e38814323bff47001ccb55b5eebb397aea8a254f3e91f57b87		 pdf-font-stream PDF embedded font (sfnt) at offset 0x11F9D 16096 bytes

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