Malicious PDF — malware analysis report

Static analysis result for SHA-256 82f8ebab4cc688ba…

MALICIOUS

PDF

65.9 KB Created: 2021-04-23 12:57:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-29
MD5: fbda7ff930bb6130e2929652ebf84c64 SHA-1: bbf7585780bb16cc56e9fce2ade67df17b56850b SHA-256: 82f8ebab4cc688bac766a2fa04a53ceefe04d1ed9b130c13c3c4fac24eb84a5b
126 Risk Score

Malware Insights

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

The PDF document is identified as malicious by ML classifiers and ClamAV, with heuristics indicating it functions as a link farm on disposable hosting. The document body, though heavily obfuscated, suggests a lure related to job interview questions. The presence of numerous embedded URLs, many pointing to seemingly unrelated domains and using 'webform' paths, indicates an attempt to redirect users to potentially malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9983

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://www.pacificsportfraservalley.com/sites/default/files/webform/zajufofagobixipisuna.pdf In PDF document text
    • https://www.mothercare.ro/sites/default/files/webform/resumes/susumijifiwef.pdfIn PDF document text
    • https://www.osgeurope.com/sites/osg-corporate.dev/files/webform/kanuvanirarotugawabu.pdfIn PDF document text
    • https://www.natsihwa.org.au/sites/default/files/webform/17947704001.pdfIn PDF document text
    • https://www.blplegal.com/sites/default/files/webform/80507347088.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/59286961246.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/1eyvgo/aqOO/~3/A3Ryygt5BCM/uplcv?utm_term=interview+questions+and+answers+for+clerical+assistantPDF link annotation
    • https://community.princeton.edu/system/files/webform/putirufulexuxibo.pdfIn PDF document text
    • https://minorsoncampus.princeton.edu/system/files/webform/kuwidiloj.pdfIn PDF document text
    • https://drones.princeton.edu/system/files/webform/94207829768.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_off0000c78c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC78C 5232 bytes
SHA-256: 28d72e4ff940d158bac2c2dca7c89711e5baa6e5ee087e85241a5fb486c37300
font_01_sfnt_off0000d979.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD979 10044 bytes
SHA-256: 0301af26649df47ad3e3ba5e5a2c98494aff96f23441fea79a850ce0f8a91bbf

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