Malicious PDF — malware analysis report

Static analysis result for SHA-256 66bdcc4048b5e41c…

MALICIOUS

PDF

76.7 KB Created: 2021-04-09 00:08:33 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-08-25
MD5: 23542b1bb0936b237f3a558eeaf2609d SHA-1: 2b4301f248dd6814f92c568fdf421376d4c742e5 SHA-256: 66bdcc4048b5e41c8211d9bdf3a7ac9b3a0886703c3f5a4e1c75eaec1c9fbc0d
186 Risk Score

Malware Insights

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

This PDF file was identified as malicious by ClamAV and an ML classifier. It contains a large number of external links, many pointing to disposable hosting, suggesting a link farm or phishing attempt. One of the embedded URLs, https://nipisod.ru/strik, is likely used to redirect users to malicious content. The document body, though heavily obfuscated, contains keywords related to 'open source flowchart software' and 'reddit', likely a lure to attract victims.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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://nipisod.ru/strik?utm_term=open+source+flowchart+software+reddit PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4420025/normal_6022bc906ca8a.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4417309/normal_5fe7871312d98.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4449783/normal_5fe179f048365.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4462354/normal_5ffeec8571f2b.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4401723/normal_604f9684e0f6c.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://4b002d3c-a55f-42ce-816c-238f848e88a9.filesusr.com/ugd/3398cc_8eb3fee352784eab8c4995531a96d265.pdf?index=trueIn PDF document text
    • https://1fa67a36-2e8b-44cc-a955-751d80433762.filesusr.com/ugd/d85e51_2240ddc8f97a4fe19577480538fd97bb.pdf?index=trueIn PDF document text
    • https://7ed754b6-a209-4558-9281-0032c7ee8ade.filesusr.com/ugd/4329d7_4370f2d78ab34e9ebcac4560e9e7283d.pdf?index=trueIn PDF document text
    • https://43cb2d18-1589-43a7-b1c5-fe1278e1c76d.filesusr.com/ugd/370b54_6efc7ad94e6647a694fb1a2c0b996290.pdf?index=trueIn PDF document text
    • https://e0220c8c-c322-4c33-af83-7c5b0fe00b66.filesusr.com/ugd/a771bd_f70a21efb4984f328a21fc814e9f3634.pdf?index=trueIn PDF document text
    • https://5090c2af-253d-40c3-bfb7-942fc6db26b0.filesusr.com/ugd/0511f5_5a9b5c3bb1704dfda3fcf35f3f6f5c2c.pdf?index=trueIn PDF document text
    • https://83d7d1d1-3661-4158-a2cc-78aa4aa39d08.filesusr.com/ugd/163759_160881d1599c41469d24d25de711d667.pdf?index=trueIn PDF document text
    • https://78a3f932-2eca-4366-91b9-d52a2f3c5f58.filesusr.com/ugd/a586f9_9bcf41602a044534bf425665a6830174.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/gawabog/jawipik.pdfIn PDF document text
    • https://36fc1fe3-b646-4cc1-b6e9-de51469aea27.filesusr.com/ugd/3eb4bd_4bb406cc2a5946ca8fdf6cf14996ec39.pdf?index=trueIn PDF document text
    • https://6c473ef0-402e-45f0-9f95-6bc7e89a6a1a.filesusr.com/ugd/5518c3_9447fb5d11514e399ff66887595117f8.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/sigobija/laing_middle_school_report_card.pdfIn PDF document text
    • https://c931c956-7f53-4e4e-96dc-27d7f003ba63.filesusr.com/ugd/b80c10_ad97cfb7de0f4261a5124b6a512dfa94.pdf?index=trueIn PDF document text
    • https://d05b2b94-0af3-401c-a6ef-75d00d0b58ae.filesusr.com/ugd/3bca44_d7195a95993e43968f19e2784444c15a.pdf?index=trueIn PDF document text
    • https://s3.amazonaws.com/sajatofubote/mipakoraguta.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_off0000ee64.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEE64 5364 bytes
SHA-256: 78ac341f7eac5c73a531a559a9b19127cc7ef713b528ff126de84ef8bbfdfc62
font_01_sfnt_off000100ac.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x100AC 10908 bytes
SHA-256: 241ca6918155d3ce7b14176ecc031a01cc5194c9d0672607547c8f586cafebd7