Malicious PDF — malware analysis report

Static analysis result for SHA-256 21d81ad1cd445ae2…

MALICIOUS

PDF

76.3 KB Created: 2021-03-18 04:26:52 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: c04a0c62705fe8ef161059af566e9be9 SHA-1: 5f0077c33abbba8a3e70bae604122a24ac1f7346 SHA-256: 21d81ad1cd445ae203746cec0d19f914c3c8306733bf4772f0abf49f30471dbe
156 Risk Score

Malware Insights

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

The PDF contains numerous external links, flagged as a link farm, directing to various PDF files hosted on external domains. The ClamAV detection and ML classifier strongly indicate malicious intent, likely for phishing or SEO spam. While no scripts were explicitly extracted, the PDF structure and embedded URIs suggest it's designed to redirect users to potentially malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9988

Heuristics 5

  • 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
  • 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://nipisod.ru/award?keyword=solving+absolute+value+equations+worksheet+pdf
    • https://cdn.sqhk.co/lugizumevemu/f2Jjcig/rafotokilolo.pdf
    • https://cdn.sqhk.co/xoberuweri/ejehjQs/best_buy_store_brooklyn_ny.pdf
    • http://mifvideo.space/guided_busway_route_map_cambridgem76wc.pdf
    • http://belkwigs.com/tinogelasakixefazodemamoqyj01.pdf
    • http://biomaniix.website/busisavelub96mw.pdf
    • https://cdn.sqhk.co/batumozi/dxeheia/butajixad.pdf
    • http://parhelifrl.space/59559639992q23ve.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://s3.amazonaws.com/sogovekevi/cambiar_teclado_espaol_android.pdf
    • https://569961a5-e6b5-462d-8b38-7193d5e7b20b.filesusr.com/ugd/a37a2e_656c3dd20764427cbce95df4b8ab46f3.pdf?index=true
    • https://eb62986f-0112-409a-9ebe-777412bc5c19.filesusr.com/ugd/26938b_ec63cc3ee0634110a0aa16541a04e177.pdf?index=true
    • https://b2f02272-107b-4032-aafc-54cdd6265a16.filesusr.com/ugd/6cf392_4d1469d4c67f4ae7bafaae4d7b18733c.pdf?index=true
    • https://d1b6b380-f15b-462b-86b5-0b089ba7d90d.filesusr.com/ugd/f99a33_a4028424e6364e59b145c2773f586874.pdf?index=true
    • https://cad90261-f038-4e8a-b384-2e0e37e6cb8c.filesusr.com/ugd/4c4e45_ec7df415a70c4294864809a911b281f5.pdf?index=true
    • https://f7b0ef4b-317e-4f07-901b-4de91a029b50.filesusr.com/ugd/50f142_4d2dfcbf9bb642b9bb95971a7be8ee93.pdf?index=true
    • https://s3.amazonaws.com/wogikokuzotaxa/minecraft_map_1._8._9.pdf
    • https://7c9e9c40-2b96-4f88-8065-b5ff5e495659.filesusr.com/ugd/3bfcae_8ee37d670b5a4a9b8b1b41f0c04fbeaa.pdf?index=true
    • https://s3.amazonaws.com/bomupi/10791097494.pdf
    • https://a1c9bafd-2917-4c1b-b79c-a4b44a941470.filesusr.com/ugd/f0f215_939db70f14fa44d7bc9706608808c228.pdf?index=true
    • https://39472683-7d43-4bc3-882b-0947a83fd973.filesusr.com/ugd/544c7e_a30040cf38d6466598f0c96060adabcf.pdf?index=true
    • http://scripts.sil.org/OFL

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ee95.bin
11fa5278d67a4548faffe3e3b38a19af516eb933e063c402b865dc9f5a3125d2		 pdf-font-stream PDF embedded font (sfnt) at offset 0xEE95 5888 bytes
font_01_sfnt_off0001029b.bin
7a66caa664732d0b2eb3dc2aaf325e26a62a08c91610d114a5824792f22bb428		 pdf-font-stream PDF embedded font (sfnt) at offset 0x1029B 11328 bytes

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