Malicious PDF — malware analysis report

Static analysis result for SHA-256 21fc8f0ef617c891…

MALICIOUS

PDF

82.2 KB Created: 2021-01-31 14:55:45 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: a3ccfc6c877be42af637d52579c0a611 SHA-1: 5c4761b7cb4687c5b5a4cb1a865ac99e224e4350 SHA-256: 21fc8f0ef617c8917d6f99dabdd58e23c7be24f7fdb5d2ff8a8ab9b9735ab3c6
126 Risk Score

Malware Insights

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

The PDF was flagged by ML and ClamAV as malicious, exhibiting characteristics of a link farm with numerous external URLs pointing to potentially malicious or phishing sites. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' indicates a deliberate attempt to create a large number of links on disposable hosting, suggesting a campaign to distribute malware or phish for credentials. While no scripts were explicitly extracted, the nature of the PDF and its embedded URLs strongly suggest it's part of a phishing or malware distribution effort, likely initiated via spearphishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • 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://bologen.ru/123?utm_term=chromium+complex+ion+colours
    • https://namikefazexu.weebly.com/uploads/1/3/1/6/131606603/5299147.pdf
    • http://sepibigejakina.22web.org/lakudu.pdf
    • https://patoxudiza.weebly.com/uploads/1/3/0/7/130739147/girifavunuti.pdf
    • https://damanula.weebly.com/uploads/1/3/1/8/131856109/seraxoze-jarakumunezew-tovorokorul-pedosateraxik.pdf
    • https://cdn.sqhk.co/mukujoripu/CBmGigW/new_call_from_cartoon_cat.pdf
    • http://gofimowekes.66ghz.com/xafarawofizar.pdf
    • https://jixejuterekafiw.weebly.com/uploads/1/3/4/5/134508928/zobosokomikon_rarajo_tididi_gozozevafub.pdf
    • http://gulidomirebo.22web.org/mikisopupogebaji.pdf
    • http://fodepurarag.22web.org/ecommerce_android_app_source_code_free.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://s3.amazonaws.com/divexikav/buwuf.pdf
    • http://fodapimogu.rf.gd/photoshop_cs5_mac.pdf
    • http://xonifovozub.epizy.com/bethesda_can_t_mods.pdf
    • https://s3.amazonaws.com/dumupa/vedamijemumidajilut.pdf
    • http://xeravujowa.epizy.com/afloat_shopping_guide_2019.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

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00010104.bin
ff5a392c93089642ac8c153ebc31502278027c82f512e3adf4498ebccbd284b7		 pdf-font-stream PDF embedded font (sfnt) at offset 0x10104 4936 bytes
font_01_sfnt_off000111a8.bin
c9311a381112812ed741a16bea88cdee013abf94a114f178b4bacfeb26552b5c		 pdf-font-stream PDF embedded font (sfnt) at offset 0x111A8 13236 bytes

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