Malicious PDF — malware analysis report

Static analysis result for SHA-256 51cf1ff35e5fb13c…

MALICIOUS

PDF

79.3 KB Created: 2021-04-03 20:41:12 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-25
MD5: 5e743f0dd984e828c2c5d58639869113 SHA-1: 1e3ce77a252d17bde2e2ad506eb86d85e7c313fb SHA-256: 51cf1ff35e5fb13c4216c609a84fd1b8ab70181ab4e6323af0148c5e570d75c2
186 Risk Score

Malware Insights

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

This PDF document was flagged as malicious by ClamAV and an ML classifier. The file embeds a large number of external links characteristic of an SEO link farm. Specific URLs and indicators for this sample are listed in the indicators section.

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=professionalism+skills+for+workplace+success+4th+edition+anderson+and+bolt PDF link annotation
    • https://static.s123-cdn-static.com/uploads/4450337/normal_6002c86697461.pdfIn PDF document text
    • https://cdn.sqhk.co/tubadaluzafu/Kwjd2ii/buxesoreki.pdfIn PDF document text
    • https://cdn.sqhk.co/xezufulozuwo/hd65KiE/mind_games_for_2_players_apk.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4418796/normal_60344cf51b554.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4380530/normal_5ff3ce003b3ea.pdfIn PDF document text
    • https://cdn.sqhk.co/fasotaluvose/vih3Eid/glitch_camo_modern_warfare.pdfIn PDF document text
    • https://cdn.sqhk.co/lolumebitana/iaicghi/bodyweight_calisthenics.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4393208/normal_5fe59361bfb46.pdfIn PDF document text
    • https://cdn.sqhk.co/simirides/lgfYjcE/21126112721.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://f06ae689-34e6-4fd9-b749-a5985747e370.filesusr.com/ugd/4117a9_761618ea5b6e4f7d86c922f73d6f69e6.pdf?index=trueIn PDF document text
    • https://c948e902-2437-43f3-9f1e-7aaad30688a7.filesusr.com/ugd/464a75_b6bbbc32dafc4f15bfde4d0d806a809e.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/pujirageg/human_development_report_in_india_2018.pdfIn PDF document text
    • https://3e1af3dc-cf37-4f58-935d-0a6065bc5ce9.filesusr.com/ugd/3ca236_c435ca5656b741cb9c88eb6adbdc1566.pdf?index=trueIn PDF document text
    • https://45e41439-46a4-4c97-84f0-155cfeda4cef.filesusr.com/ugd/9d7ad9_2c42852c37e746c78582b66ff23f52bb.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/64b0ac84-2927-4841-9a29-06053a9551ca/cuanto_m2_tiene_un_metro_cuadrado.pdfIn PDF document text
    • https://755d026c-fd58-4633-9ca9-8af24261f473.filesusr.com/ugd/4622eb_612db4f4b04e4d5fad39d6aba7af96e2.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/jevedijadiki/disable_bixby_android_pie.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/4cc828af-18a7-4501-bd81-2ec4bde5a666/32361058370.pdfIn PDF document text
    • https://2dc0326d-ac60-47d8-bf46-f2dc9d334570.filesusr.com/ugd/21b4a7_784c50db849a4dc5b090f8ef8b9cd4f4.pdf?index=trueIn PDF document text
    • https://7ef5d8b8-74ac-4e0a-b0a0-fa61ca6462a8.filesusr.com/ugd/23e9be_8e063eb5f3104e23870093cb74bf25ad.pdf?index=trueIn 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_off0000f4a5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF4A5 5780 bytes
SHA-256: 0047931455531f2c04454888f6aef0484a5855ac6cf46653383114ea99413112
font_01_sfnt_off00010838.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10838 11396 bytes
SHA-256: 2450b9fd90a88e23f991e03057f602c42c6c09af6a54fb18a49b8c2eaec13f68