Malicious PDF — malware analysis report

Static analysis result for SHA-256 b99a571f1c59e955…

MALICIOUS

PDF

79.9 KB Created: 2021-03-15 12:48:39 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-08-25
MD5: 3303e6ee86a9ac32ac63d88418ea8e1d SHA-1: d7f3f603a5213e3418492c9594b33506549b374c SHA-256: b99a571f1c59e95592db18812df01456c1e4b4af78a247d8cc89123a771e1f37
126 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous external URIs, many pointing to disposable hosting, suggesting a link farm designed to distribute malicious content. The document body, though heavily obfuscated, appears to be a lure related to a worksheet answer key, aiming to trick users into clicking embedded links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

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://kuzutuzo.ru/wix?keyword=section+2+reinforcement+properties+of+matter+worksheet+answer+key PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4494165/normal_603ab236bdbc9.pdfIn PDF document text
    • https://cdn.sqhk.co/woxiwovar/igjhjhL/lost_echo_resonance.pdfIn PDF document text
    • http://napojenewojiro.22web.org/malamunilagumepapoviwudep.pdfIn PDF document text
    • https://cdn.sqhk.co/dejegekonula/Ihhkicm/2_pics_1_word_answers_level_25.pdfIn PDF document text
    • http://pobumur.iblogger.org/segmented_income_statement_contribution_format.pdfIn PDF document text
    • https://cdn.sqhk.co/firokizita/epUgg7r/wavebepagatogesejekeno.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4385848/normal_60397384c183f.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4473892/normal_601a0030cb1f8.pdfIn PDF document text
    • https://cdn.sqhk.co/kasesiseb/VuujbgJ/verizon_authorized_retailer_cellular_plus_gillette_wy.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4449998/normal_5fdb72e3e09c5.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4416923/normal_60450aaae39f1.pdfIn PDF document text
    • http://tasiperop.medianewsonline.com/mexunademigurejufaxelotiv.pdfIn PDF document text
    • http://putifid.iblogger.org/gasunojizatuzedarumavurew.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4422390/normal_5feb3c6c326a9.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4370288/normal_5fee831e236f2.pdfIn PDF document text
    • https://cdn.sqhk.co/xexogataza/jahagfn/40314948978.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4393035/normal_603cef60c1e0a.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4423732/normal_602a352555fd7.pdfIn PDF document text
    • http://bajifepeselok.sportsontheweb.net/differentiation_of_algebraic_functions_example_problems.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://dujofaxuro.rf.gd/suzewikorukixese.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/29146831-25af-4b30-8bd8-ef731fbca0ab/zao_an_meaning.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/739772a6-0062-494d-82ff-a485381b1811/39540306959.pdfIn PDF document text
    • http://nozozuwovore.atwebpages.com/diagrama_de_casos_de_uso_ejercicios_resueltos.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/c61daec1-db1f-4c1f-8584-b99415d54574/15568615238.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_off0000f8dd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF8DD 5716 bytes
SHA-256: b8d9a99a1d35b756fe42953d12c049fabb71edb10302bb262cdb18f721515d05
font_01_sfnt_off00010c4c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10C4C 10344 bytes
SHA-256: 3bc1be8607910734ee622579d70a0b0468914dddb155fe5e8fea5b86afb14b81