Malicious PDF — malware analysis report

Static analysis result for SHA-256 90ca8d3e54ddcacc…

MALICIOUS

PDF

68.1 KB Created: 2021-04-15 20:05:18 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-23
MD5: 52e7235ce8910b1588f1e871f9467f82 SHA-1: b8d68a1d7748737a8b2fa23ecc4dd39aa6a35ba9 SHA-256: 90ca8d3e54ddcacc01a049c7c6f4f4eb5d500ea1928e6b5010e25b51bf67fb77
126 Risk Score

Malware Insights

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

The PDF document was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs, many pointing to disposable or unknown domains, and is identified as a link farm. The document body is heavily obfuscated, but the presence of external URIs and the link farm heuristic strongly suggest an attempt to redirect users to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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://ambrose.edu/sites/default/files/webform/61391242106.pdf In PDF document text
    • http://www.guninetwork.org/system/files/webform/heirri_proposals/44437875789.pdfIn PDF document text
    • https://www.osgeurope.com/sites/osg-corporate.dev/files/webform/19824824677.pdfIn PDF document text
    • https://www.jsif.org/sites/default/files/webform/kedoruxanagavapiwo.pdfIn PDF document text
    • http://russian-ice-spb.ru/sites/default/files/webform/files/zatepatepekaberemosigedix.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/dozigax.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/99368311749.pdfIn PDF document text
    • http://pilgrimland.com/sites/default/files/webform/resume-uploads/41345860665.pdfIn PDF document text
    • https://www.telluridescience.org/sites/default/files/tstc-applications/90077644064.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/fabifuturofutip.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/LPIa9PGmDLg/uplcv?utm_term=what+size+are+shop+vac+hosesPDF link annotation
    • https://minorsoncampus.princeton.edu/system/files/webform/wetesagepe.pdfIn PDF document text
    • https://www.healthdata.org/sites/default/files/resumes/fanonexujezurexuli.pdfIn PDF document text
    • https://www.ice.cam.ac.uk/sites/www.ice.cam.ac.uk/files/webform/wosevojowavinojefe.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_off0000cd49.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCD49 5112 bytes
SHA-256: 339db93e0bac641cff7dd26b57f26509594637380f639083c1a14692c64898cd
font_01_sfnt_off0000dec2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDEC2 11108 bytes
SHA-256: da0b9666783789f15f03d9fdefffe659c1c7d07dbea9b207388cae01054cc6cf