Malicious PDF — malware analysis report

Static analysis result for SHA-256 ac5b94c786dd6c46…

MALICIOUS

PDF

78.8 KB Created: 2021-04-22 07:51:06 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-26
MD5: 9b8bf586bcd0907fa03af3db9266fea1 SHA-1: 774bb27ee0b455d045fee5d6f21d8d0c0916be33 SHA-256: ac5b94c786dd6c46c1105f1b2959757ea659e254a6cee95ef52421252f5843b1
126 Risk Score

Malware Insights

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

The PDF file was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. The document body, though heavily obfuscated, contains references to 'Microsoft data analyst certification reddit', suggesting a lure. The presence of numerous external URIs, many pointing to PDF files hosted on various domains, indicates a link farm designed to redirect users, likely to a malicious site or for further payload delivery.

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://www.termis.org/system/files/webform/67198091979.pdf In PDF document text
    • https://ambrose.edu/sites/default/files/webform/mamak.pdfIn PDF document text
    • https://www.cdcplumbing.com/sites/default/files/webform/contact-us/sawifujemenolezaf.pdfIn PDF document text
    • http://oaklandchildcare.org/sites/default/files/webform/55178968397.pdfIn PDF document text
    • https://www.uts.cw/sites/default/files/webform/pugixenarewowu.pdfIn PDF document text
    • https://extranet.blanchisserie-toulousaine-de-sante.com/sites/extranet.blanchisserie-toulousaine-de-sante.com/files/documents/justificatifs/29410319198.pdfIn PDF document text
    • https://www.pharoxglobal.com/sites/default/files/webform/7322176875.pdfIn PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/6948618973.pdfIn PDF document text
    • https://grossenbacher.co.nz/en/system/files/avoidance-training-certificates/3242210986.pdfIn PDF document text
    • https://www.blplegal.com/sites/default/files/webform/3097059720.pdfIn PDF document text
    • https://natsihwa.org.au/sites/default/files/webform/80931084074.pdfIn PDF document text
    • https://www.natsihwa.org.au/sites/default/files/webform/xexazud.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/ngfLrbzwjls/uplcv?utm_term=microsoft+data+analyst+certification+redditPDF link annotation
    • https://campusrec.princeton.edu/system/files/webform/34970544405.pdfIn PDF document text
    • https://campusrec.princeton.edu/system/files/webform/rilawadabovoxilezevateg.pdfIn PDF document text
    • https://printandmail.princeton.edu/system/files/webform/98467125123.pdfIn PDF document text
    • https://campusrec.princeton.edu/system/files/webform/18758627140.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_off0000f6b1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF6B1 5124 bytes
SHA-256: bf061d59d86d1f5bf5027a434f1d87adebb423b80a5526151fa1935197a32537
font_01_sfnt_off00010840.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10840 10936 bytes
SHA-256: cc5fbf81b8af5c93a1289cdd5b7a50b8cee0495dbd58abee466b0a412468b2e5

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