Malicious PDF — malware analysis report

Static analysis result for SHA-256 526863d5b6d2384d…

MALICIOUS

PDF

72.2 KB Created: 2021-04-07 20:56:05 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-06-28
MD5: fc666ad5d96e46b6de77b2d0c7a624e9 SHA-1: 998091efca18c143b0d609e5c285c701a4d88ffe SHA-256: 526863d5b6d2384d0455e4f99087433236d562bcfefd06f088a3f0b64eed982e
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm on disposable hosting, with numerous embedded URLs pointing to external resources. The primary malicious URL identified is http://portal-mysigma.com/system/files/student-proof/47432021317.pdf, which is likely used to host or redirect to a malicious payload.

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 http://portal-mysigma.com/system/files/student-proof/47432021317.pdf In PDF document text
    • https://ambrose.edu/sites/default/files/webform/fulakosilukubusovugatupus.pdfIn PDF document text
    • https://extranet.blanchisserie-toulousaine-de-sante.com/sites/extranet.blanchisserie-toulousaine-de-sante.com/files/documents/justificatifs/bugoxugokerudanetisene.pdfIn PDF document text
    • http://www.pbttphtk.gov.my/sites/default/files/webform/88462653206.pdfIn PDF document text
    • https://vectorcorp.net/sites/default/files/webform/resume/sabaw.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/32675510575.pdfIn PDF document text
    • https://www.newburghgroup.com/sites/default/files/webform/resumes/tikijoti.pdfIn PDF document text
    • http://www.pbttphtk.gov.my/sites/default/files/webform/73261430544.pdfIn PDF document text
    • http://portal-mysigma.com/system/files/student-proof/41429692510.pdfIn PDF document text
    • https://www.osgeurope.com/sites/osg-corporate.dev/files/webform/10654010608.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://feedproxy.google.com/~r/Uplcv/~3/ngfLrbzwjls/uplcv?utm_term=anatomie+du+bassin+de+la+femme+pdfPDF link annotation
    • https://printandmail.princeton.edu/system/files/webform/ziwilijevugibapuvoboka.pdfIn PDF document text
    • https://ubmemeaensoprod.s3.amazonaws.com/ifsec_international/call_for_papers/2021/03/60395266702.pdfIn PDF document text
    • https://community.princeton.edu/system/files/webform/putirufulexuxibo.pdfIn PDF document text
    • https://thesanfordschool.asu.edu/sites/default/files/webform/xumigisapiwonatidokababup.pdfIn PDF document text
    • https://lib.asu.edu/system/files/webform/bejugejotofetuxiw.pdfIn PDF document text
    • https://minorsoncampus.princeton.edu/system/files/webform/wetesagepe.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_off0000db4f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDB4F 5220 bytes
SHA-256: 34346d49e31d6cd37aed815ea6590649769ffc0e370381cf7d933ea5859f5615
font_01_sfnt_off0000ed00.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED00 11620 bytes
SHA-256: 28b680b1718ab1c426b3b361d8a0304339f18a3a84983af940a459d099edd2a0

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