Malicious PDF — malware analysis report

Static analysis result for SHA-256 989e761f00dbea41…

MALICIOUS

PDF

92.0 KB Created: 2021-04-10 19:07:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-08-20
MD5: bd03d204dc62db67024295c885e16adf SHA-1: 7ef421171523b649467eb1554d666b74d11b0a4a SHA-256: 989e761f00dbea4110f0102d8634effc47ee9b20f77fb14e855f8ce1b45f0b9e
186 Risk Score

Malware Insights

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

This PDF file is identified as malicious by ML classifiers and ClamAV, indicating a phishing or trojan threat. It contains a large number of external links, many of which are part of a link farm designed to manipulate search engine results, with one prominent link pointing to 'https://vilenefex.ru/strik?utm_term=ielts+academic+writing+sample+answers+task+1'. The document body is heavily obfuscated and unreadable, but the presence of numerous external links suggests an attempt to redirect users to potentially malicious websites, possibly for credential harvesting or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • 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 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.
  • 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://vilenefex.ru/strik?utm_term=ielts+academic+writing+sample+answers+task+1 PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4460071/normal_606ab67c5eee0.pdfIn PDF document text
    • http://chempion.coffee/amd_a4_9125_radeon_r3_driversqft1f.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4498348/normal_6056cee1c7d5b.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4481539/normal_60528081c854b.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4410217/normal_601145882f751.pdfIn PDF document text
    • http://alifan.store/tiktok_starbucks_drink_white_mocha_caramel8ecf0.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4383798/normal_5fe4f62f806db.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4384468/normal_5fe107665b154.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://s3.amazonaws.com/davawina/sedixus.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/16e4a02c-e466-48ed-939e-013952eceda4/gizuvaxaze.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/5602b544-483d-4660-b4d8-a3c9378993de/36270791801.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/fd53c202-ca6e-440e-885a-fb7a8139b21f/97263111135.pdfIn PDF document text
    • https://s3.amazonaws.com/kezemiradigu/timefuxovimu.pdfIn PDF document text
    • https://34e223d5-b18a-4f89-96b3-7c58aa965d90.filesusr.com/ugd/440e29_d36125e4747e478c9c8f7aa48918ace8.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/90133ca6-24fd-457e-a683-7e59050f937e/19212912339.pdfIn PDF document text
    • https://s3.amazonaws.com/jidagafinuxesu/platform_sutra_commentary.pdfIn PDF document text
    • https://034b020c-baab-45d1-b3ff-c950d21f9178.filesusr.com/ugd/3c93bc_6b8e2f0391b54d26bb195aea21d6f438.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/b0b089a5-e4f3-4ada-a82a-36410e23f24a/nuzudusujizukepi.pdfIn PDF document text
    • https://s3.amazonaws.com/zidosozawok/movie_hd_site.pdfIn PDF document text
    • https://s3.amazonaws.com/zarevizebi/arena_of_evolution_red_tides_apk.pdfIn PDF document text
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00012b38.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12B38 5540 bytes
SHA-256: 3eeb94c9a73243796694c4f055cd5d22d8a48eff02fc58a4148dc57e246d8ed8
font_01_sfnt_off00013e0d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13E0D 10764 bytes
SHA-256: 265eac3de09182332861f751ef9d2387262bf5aed5cde8590f6ef91c14855316