Malicious PDF — malware analysis report

Static analysis result for SHA-256 e3bd4e7a43941f0b…

MALICIOUS

PDF

66.6 KB Created: 2021-04-11 13:07:41 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-26
MD5: a296ff70972b9bafb8fdbbe11242e7cd SHA-1: 99f0f3fd05462febef51ae3db0b285b2f764b5d1 SHA-256: e3bd4e7a43941f0b8241b6c522bb05841d60a0c582731d2697aca9e47cf8f5a5
126 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. The document body, though heavily obfuscated, contains references to wkhtmltopdf and a date, suggesting it might be a generated document. The presence of numerous external URIs, many pointing to potentially disposable domains or subdomains, indicates a link farm or redirection mechanism designed to lead the user to a malicious site. While no scripts were explicitly extracted, the PDF format itself can embed JavaScript, which is often used for malicious redirection or exploitation.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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 https://ambrose.edu/sites/default/files/webform/99544266771.pdf In PDF document text
    • http://portal-mysigma.com/system/files/student-proof/41429692510.pdfIn PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/78191676466.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/vopezupudatirarib.pdfIn PDF document text
    • http://portal-mysigma.com/system/files/student-proof/9555400870.pdfIn PDF document text
    • https://www.uts.cw/sites/default/files/webform/tidenopuzi.pdfIn PDF document text
    • http://www.guninetwork.org/system/files/webform/heirri_proposals/38059385999.pdfIn PDF document text
    • http://www.pbttphtk.gov.my/sites/default/files/webform/33269367294.pdfIn PDF document text
    • https://www.jsif.org/sites/default/files/webform/94808830073.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/GLLx1DTH0VQ/uplcv?utm_term=jaguar+s+type+2001+workshop+manualPDF link annotation
    • https://minorsoncampus.princeton.edu/system/files/webform/posilo.pdfIn PDF document text
    • https://www.ice.cam.ac.uk/sites/www.ice.cam.ac.uk/files/webform/xegenaxug.pdfIn PDF document text
    • https://printandmail.princeton.edu/system/files/webform/zixulupuritijidegebi.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_off0000c852.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC852 5808 bytes
SHA-256: ead738c17af48700efa06ae9223072aa5e2c0b45d1c29966b753b68e7c772c65
font_01_sfnt_off0000dc0e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDC0E 9888 bytes
SHA-256: bb59927d6078ffac842b75f6f2c99e0784ebd51ae01ee471d298736086912223

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