Malicious PDF — malware analysis report

Static analysis result for SHA-256 73a4f751ffb7cdbe…

MALICIOUS

PDF

70.9 KB Created: 2021-04-20 06:24:30 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-26
MD5: 7f37dedbd965a1044f2b4c11923f950b SHA-1: 52531a280d91efdea763c3e045444a1fedcd3fc2 SHA-256: 73a4f751ffb7cdbeb8ddbf631a54fe585a96f79de44c1704df5575fcaeadba13
126 Risk Score

Malware Insights

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

The file is a PDF document that has been classified as malicious by ML and ClamAV, indicating it is a phishing trojan. The document body, though heavily obfuscated, suggests a lure related to 'Julian date calendar leap year pdf'. Several external URIs were extracted, with one pointing to a potential link farm, which is a common tactic for phishing campaigns. No scripts were extracted from this sample, but the PDF structure and heuristic firings strongly suggest malicious intent.

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://grossenbacher.co.nz/en/system/files/avoidance-training-certificates/tojawi.pdf In PDF document text
    • https://grossenbacher.co.nz/en/system/files/avoidance-training-certificates/13178745316.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/kizosilubim.pdfIn PDF document text
    • https://www.jts.org.jo/sites/default/files/webform/96043924660.pdfIn PDF document text
    • https://www.natsihwa.org.au/sites/default/files/webform/86947183128.pdfIn PDF document text
    • http://oaklandchildcare.org/sites/default/files/webform/80411930416.pdfIn PDF document text
    • http://www.sumnercountyhospital.org/sites/default/files/webform/72664382884.pdfIn PDF document text
    • https://www.blplegal.com/sites/default/files/webform/pifijolaj.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/durigoxilakomisi.pdfIn PDF document text
    • https://www.uts.cw/sites/default/files/webform/suvexaxobufakup.pdfIn PDF document text
    • https://www.a1touchsolution.nl/sites/default/files/26511902049.pdfIn PDF document text
    • https://extranet.blanchisserie-toulousaine-de-sante.com/sites/extranet.blanchisserie-toulousaine-de-sante.com/files/documents/justificatifs/vinoku.pdfIn PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/zavemazawutojene.pdfIn PDF document text
    • http://russian-ice-spb.ru/sites/default/files/webform/files/69309865186.pdfIn PDF document text
    • http://www.muttypawsacademy.com/sites/default/files/webform/vaccines/nojezajewi.pdfIn PDF document text
    • https://aboss.by/sites/default/files/webform/32639212941.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=julian+date+calendar+leap+year+pdfPDF link annotation
    • 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_off0000d67b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD67B 5064 bytes
SHA-256: b4f955e577762bf2e7d0c6b28edd45fc01a7c6f818d748b885561c8dbe210abe
font_01_sfnt_off0000e7d5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE7D5 11400 bytes
SHA-256: 0384bbbe5457ea195932f68a44a77dd6a11b2b062ad4c8f7172e575de6487e74

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