Malicious PDF — malware analysis report

Static analysis result for SHA-256 404b73b88550b5d1…

MALICIOUS

PDF

76.8 KB Created: 2021-04-20 14:08:26 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-29
MD5: a924c896c5ae79da9dd11eca3d0e42ca SHA-1: c92b8e1e9edcb85c0386217789a410ff43b3a69e SHA-256: 404b73b88550b5d13a24eea5a517a4826aa44cc4f6b5c9ecd13b334c41c161bd
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, containing numerous external URIs pointing to various domains. The document body is heavily obfuscated and unreadable, suggesting it is not intended for direct user interaction but rather to facilitate the redirection to malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

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://www.a1touchsolution.nl/sites/default/files/95216779236.pdf In PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/53132673180.pdfIn PDF document text
    • https://www.natsihwa.org.au/sites/default/files/webform/bukitonixoravutewoluba.pdfIn PDF document text
    • http://www.grotekeukens.be/sites/default/files/webform/gmawards2018/41850888982.pdfIn PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/todoxobolukajit.pdfIn PDF document text
    • https://www.telluridescience.org/sites/default/files/tstc-applications/kuvusuwube.pdfIn PDF document text
    • https://architecturaldesigninc.com/sites/default/files/sujuxot.pdfIn PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/16831560309.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/zabufenopi.pdfIn PDF document text
    • https://www.a1touchsolution.nl/sites/default/files/xofarazenufokedakuzos.pdfIn PDF document text
    • https://www.natsihwa.org.au/sites/default/files/webform/tesogiruzan.pdfIn PDF document text
    • https://www.blplegal.com/sites/default/files/webform/lolavojirubopikumu.pdfIn PDF document text
    • https://www.mothercare.ro/sites/default/files/webform/resumes/tawapiseligimagawawujimo.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.daltonmaag.com/In PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/ngfLrbzwjls/uplcv?utm_term=ff14+heavensward+art+bookPDF link annotation
    • https://printandmail.princeton.edu/system/files/webform/42849177422.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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d18b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD18B 4196 bytes
SHA-256: 05ac7f752042a909c79894958375e3b79e3264d6f2c66986f1e9dfba59f4de42
font_01_sfnt_off0000e077.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE077 5152 bytes
SHA-256: b525bce493beef130848060d599eb0ced0593bd05c4f11500b9f7be5814abdae
font_02_sfnt_off0000f207.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF207 10668 bytes
SHA-256: 358294741ea177627fd8d8e4a5ba6207ea1361a290f012084880b777185de8f7
font_03_sfnt_off0001169c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1169C 4324 bytes
SHA-256: 7f6049e5011acf0e8581793f2bc2bb947aac2929fdb77abc318b2a6155c1ef71

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