Malicious PDF — malware analysis report

Static analysis result for SHA-256 21ba4fd699a07b74…

MALICIOUS

PDF

97.8 KB Created: 2021-04-26 21:28:06 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-26
MD5: 10660d215c3969b611a7331b0a5e0b30 SHA-1: 599c27996d78a84d0c32572bd9ceb366e6c77fb4 SHA-256: 21ba4fd699a07b741004ea806b08dbd4f4c02a2a640cf0f002c026a02fcd4a95
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. It contains numerous embedded URLs, many of which are hosted on disposable domains and appear to be part of a link farm, suggesting a phishing or credential harvesting attempt. The document body, though heavily obfuscated, contains references to salary information, likely a lure to entice users to click the malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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 http://oaklandchildcare.org/sites/default/files/webform/wafawujozovu.pdf In PDF document text
    • https://www.enwidth.com/sites/default/files/webform/resumes/fudigebifofonixetizitalu.pdfIn PDF document text
    • https://web.liderpapel.com/sites/default/files/webform/dojoxopanikofogenag.pdfIn PDF document text
    • https://architecturaldesigninc.com/sites/default/files/72694480293.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/65000750087.pdfIn PDF document text
    • https://www.telluridescience.org/sites/default/files/tstc-applications/30232074114.pdfIn PDF document text
    • http://portal-mysigma.com/system/files/student-proof/72808970040.pdfIn PDF document text
    • https://www.a1touchsolution.nl/sites/default/files/35095474677.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://www.muttypawsacademy.com/sites/default/files/webform/vaccines/2944445507.pdfIn PDF document text
    • https://aboss.by/sites/default/files/webform/32639212941.pdfIn PDF document text
    • https://www.osgeurope.com/sites/osg-corporate.dev/files/webform/povufukawonafano.pdfIn PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/16831560309.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.daltonmaag.com/In PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/PmAiG5ZyT-k/uplcv?utm_term=delta+flight+attendant+salary+glassdoorPDF link annotation
    • https://community.princeton.edu/system/files/webform/4167827641.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00012e20.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12E20 5056 bytes
SHA-256: 51f3e3bbba6eec9c62bf66f8141843ed6b67494b4776e529adc28b31b3baa3c3
font_01_sfnt_off00013f4c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13F4C 13428 bytes
SHA-256: dacdadb74b8eec78412433983dde51f6c9d5ec0e510ee6c6280976106a70156f
font_02_sfnt_off00016c06.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x16C06 4324 bytes
SHA-256: a542ec26cea93e049a2e27cd59b1347dd9bbdea13775fd7b822b3c2b3136116f

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