Malicious PDF — malware analysis report

Static analysis result for SHA-256 91c43efc17cab4cc…

MALICIOUS

PDF

80.4 KB Created: 2021-04-02 12:01:26 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: ec95830b2c5676ddc49fca647045d0e6 SHA-1: 5dd8977019e54d1890541ca262969582db87f5d8 SHA-256: 91c43efc17cab4cc3b8922af3df8a86eac7c2cf3ce4198cf2d38064c2e8c7b50
156 Risk Score

Malware Insights

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

The PDF contains a large number of external links, many of which are dynamically generated and point to other PDFs, suggesting a link farm for SEO manipulation or malware distribution. The ML classifier and ClamAV detection strongly indicate malicious intent. The document body, though heavily obfuscated, appears to be related to a watch battery replacement, a common lure for phishing or malware.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://dafemum.ru/strik?utm_term=timex+women%2527s+ironman+watch+battery+replacement
    • https://vewejefimubi.weebly.com/uploads/1/3/4/1/134108794/zizisumowobefa.pdf
    • https://cdn.sqhk.co/bidusowo/hhc1Khi/my_boy_emulator_pokemon_roms.pdf
    • https://vezinamitin.weebly.com/uploads/1/3/5/9/135984824/2505364.pdf
    • https://cdn.sqhk.co/gawagunikuw/83oht0m/mebovoxamagetisigu.pdf
    • http://fonivoguko.medianewsonline.com/mathe_bungen_klasse_7_rationale_zahlen.pdf
    • https://cdn.sqhk.co/datujisukebe/mjbghhg/dijemol.pdf
    • https://cdn.sqhk.co/fasaparoba/hjK4nXV/wisenotujawukalubusazeg.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • http://vulopekusape.atwebpages.com/79560155112.pdf
    • https://2eb5e741-fe40-4e13-9a70-20af0821b154.filesusr.com/ugd/6cf56c_d80bdd9b1adf4965847f87180998fb8e.pdf?index=true
    • http://mogixos.atwebpages.com/35328049836.pdf
    • https://a121017b-3fb3-450c-9156-48dd71a9bf80.filesusr.com/ugd/07625c_6c4b64dd76a745d782aba4b2d09c3325.pdf?index=true
    • http://fedonefekipide.myartsonline.com/watuxajurutajevul.pdf
    • http://pijosufun.myartsonline.com/marathi_law_books_free_download.pdf
    • https://uploads.strikinglycdn.com/files/4d47a148-4571-4165-98aa-e2f6722898d9/zagujekoxinonosujowovela.pdf
    • https://uploads.strikinglycdn.com/files/0c450a6b-1f12-4c74-9f8d-99d25978cccd/desire_to_learn_sru.pdf
    • https://uploads.strikinglycdn.com/files/f005cf7e-f35b-4df3-a18e-4a50ba67ec69/essay_on_human_understanding_john_locke_summary.pdf
    • https://42e65457-ec34-4553-8979-78b6e302f774.filesusr.com/ugd/f1976d_73bc837247604efca9dbda52a3ce6451.pdf?index=true
    • https://4c8cc264-4606-483b-a6fd-3ab48ba5c15a.filesusr.com/ugd/c626f4_d07be5681cf041fc80346833ad8df9e4.pdf?index=true
    • https://01c4c9a3-ee74-4db9-a65d-799443b8dbf1.filesusr.com/ugd/a64c8c_dd87f28f61d945a5b3ee87e1804bc62c.pdf?index=true
    • https://uploads.strikinglycdn.com/files/0bc29751-41d3-421e-ac26-6b18b140aac6/898207344.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_off0000f86e.bin
3b4d7bd071955979c5bfef883de69fd3e16bfa15ec23c0c19620941a22acce70		 pdf-font-stream PDF embedded font (sfnt) at offset 0xF86E 5556 bytes
font_01_sfnt_off00010b3f.bin
5e2cabc205ec240bb73e54c68c3e618f51cc1f6f0337166197baca6dc237a8d9		 pdf-font-stream PDF embedded font (sfnt) at offset 0x10B3F 11508 bytes

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