Malicious PDF — malware analysis report

Static analysis result for SHA-256 8f888645dd42fd9e…

MALICIOUS

PDF

80.6 KB Created: 2021-04-09 19:37:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-29
MD5: 5de72aa63068195c13cb0cfec164f8a8 SHA-1: 2d40233ae3b95b223aac604c5099ea37e0c6e92f SHA-256: 8f888645dd42fd9e98579fd0815563ab05b02b52eb25d86dd9356f0749a467cb
126 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious, with heuristics indicating it functions as a link farm pointing to multiple external URLs. The presence of embedded URLs and the PDF structure suggest an attempt to redirect users to potentially malicious sites, likely for phishing or to download further payloads. No scripts were extracted, but the overall structure and heuristic firings strongly indicate malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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 http://cicatsalud.com/html/sites/default/files/webform/jedirokadezat.pdf In PDF document text
    • https://grossenbacher.co.nz/en/system/files/avoidance-training-certificates/95133977644.pdfIn PDF document text
    • https://europa-ts.ru/sites/default/files/webform/totikejeropisatuzubafaba.pdfIn PDF document text
    • https://www.ofalloncasting.com/sites/default/files/webform/68406293253.pdfIn PDF document text
    • https://www.osgeurope.com/sites/osg-corporate.dev/files/webform/bedadijone.pdfIn PDF document text
    • https://extranet.blanchisserie-toulousaine-de-sante.com/sites/extranet.blanchisserie-toulousaine-de-sante.com/files/documents/justificatifs/pefusoxewirevujilo.pdfIn PDF document text
    • http://oaklandchildcare.org/sites/default/files/webform/26688185713.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/~3/3vuEKuznOb8/uplcv?utm_term=anne+gaelle+riccio+nuePDF link annotation
    • https://www.vub.be/sites/vub/files/webform/piwolumubixu.pdfIn PDF document text
    • https://thesanfordschool.asu.edu/sites/default/files/webform/85266863194.pdfIn PDF document text
    • https://www.healthdata.org/sites/default/files/resumes/78922999772.pdfIn PDF document text
    • https://community.princeton.edu/system/files/webform/22535495660.pdfIn PDF document text
    • https://lib.asu.edu/system/files/webform/sikukuditizituxabisezopel.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://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text
    • http://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_004_off00010f7a.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x10F7A 21196 bytes
SHA-256: 879340cfc2921783c3928ac2764fa02c2c06a6c7dc254e1846a9632af086041d
font_00_sfnt_off0000d4c4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD4C4 4776 bytes
SHA-256: 5908be0dee2430c4ab2b5f44379d3642b3c4c353be38faa85d48f52898e67c00
font_01_sfnt_off0000e517.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE517 14200 bytes
SHA-256: b313cbad1adb73ab73e1fbf57f976178b7e0ec9dee7353aeadf97a353251ea6f

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