Malicious PDF — malware analysis report

Static analysis result for SHA-256 a928384b366fd83f…

MALICIOUS

PDF

72.2 KB Created: 2021-04-24 05:51:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-11
MD5: 05b7f888d7906571c9b7d854677b00d1 SHA-1: 26b201312ed9f392c9b1f935ece7530424f0a62c SHA-256: a928384b366fd83f0f6e9f6d5c9ef99517da0ae9d9ab54ac1a8040d6b3c52bea
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.001 Malicious Link T1059.007 JavaScript

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs, many pointing to domains that appear to be part of a link farm designed to obscure the ultimate destination. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' indicates a deliberate attempt to create a deceptive structure. While no scripts were explicitly extracted, the nature of the embedded URLs and the detection as a trojan suggest it likely leads to a malicious site for further exploitation.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://vectorcorp.net/sites/default/files/webform/resume/dofivefodazewinewes.pdf In PDF document text
    • https://ambrose.edu/sites/default/files/webform/rebunedirewe.pdfIn PDF document text
    • https://www.ofalloncasting.com/sites/default/files/webform/66890294103.pdfIn PDF document text
    • https://www.jwico.com/sites/default/files/webform/47965191786.pdfIn PDF document text
    • http://oaklandchildcare.org/sites/default/files/webform/85322732160.pdfIn PDF document text
    • https://www.blplegal.com/sites/default/files/webform/pifijolaj.pdfIn PDF document text
    • https://www.osgeurope.com/sites/osg-corporate.dev/files/webform/3563422068.pdfIn PDF document text
    • https://www.telluridescience.org/sites/default/files/tstc-applications/dadesiludidogujuta.pdfIn PDF document text
    • https://www.natsihwa.org.au/sites/default/files/webform/welukugipevodabarovefeweb.pdfIn PDF document text
    • https://www.ofalloncasting.com/sites/default/files/webform/nunemoxajusadokuxilebe.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/46846662681.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/skout/mBVl/~3/cv9VXjIrmdE/uplcv?utm_term=rca+tablet+power+adapterPDF link annotation
    • https://www.healthdata.org/sites/default/files/resumes/58023923203.pdfIn PDF document text
    • https://community.princeton.edu/system/files/webform/40347257249.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
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000c472.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC472 5128 bytes
SHA-256: 80a41e908f5e9c457420ad360aeeb9b09f9f2510d97d8e40e363915432979218
font_01_sfnt_off0000d602.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD602 12372 bytes
SHA-256: 319b9038e3bb0e4529fb7fae29130ae0fe78fc4a865a1c8e345b1e718f42f2e0
font_02_sfnt_off0000ff1f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFF1F 16140 bytes
SHA-256: 1ffca1ef16be5e2ec436e77f9211a88ad3199dc781cb76600401cc2e2c7dce6d

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