Malicious PDF — malware analysis report

Static analysis result for SHA-256 f61c664d720f8f2f…

MALICIOUS

PDF

67.7 KB Created: 2021-04-13 08:54:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-29
MD5: b891a053aa267f0938f9612149576b0c SHA-1: 71d3617ff9ec454df9b01da0f4a35f3d490400c2 SHA-256: f61c664d720f8f2f2f17f20ba337be8a4202566b871055b13589ca223804ffaa
126 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, directing users to multiple external URLs, some of which are hosted on potentially disposable domains. While no scripts were explicitly extracted, the PDF structure and the nature of the heuristics suggest it may leverage embedded JavaScript or other mechanisms to facilitate redirection to malicious sites.

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://www.osgeurope.com/sites/osg-corporate.dev/files/webform/28911573484.pdf In PDF document text
    • https://grossenbacher.co.nz/en/system/files/avoidance-training-certificates/13471650610.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/2306024917.pdfIn PDF document text
    • https://www.osgeurope.com/sites/osg-corporate.dev/files/webform/3563422068.pdfIn PDF document text
    • http://www.birdlifebotswana.org.bw/sites/default/files/webform/sightings-sketches/13349970620.pdfIn PDF document text
    • http://oaklandchildcare.org/sites/default/files/webform/veser.pdfIn PDF document text
    • https://grossenbacher.co.nz/en/system/files/avoidance-training-certificates/95133977644.pdfIn PDF document text
    • http://portal-mysigma.com/system/files/student-proof/woximinel.pdfIn PDF document text
    • https://www.natsihwa.org.au/sites/default/files/webform/tuwagamutavuvefofufeniz.pdfIn PDF document text
    • http://www.guninetwork.org/system/files/webform/heirri_proposals/32710798707.pdfIn PDF document text
    • https://www.osgeurope.com/sites/osg-corporate.dev/files/webform/27880179426.pdfIn PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/30253637425.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/PmAiG5ZyT-k/uplcv?utm_term=professor+max+randall+cambridgePDF link annotation
    • https://printandmail.princeton.edu/system/files/webform/83328436210.pdfIn PDF document text
    • https://printandmail.princeton.edu/system/files/webform/54002061309.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_off0000cb63.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCB63 5548 bytes
SHA-256: edbac91d0f32a5f4d31c4c57e2885f4b0e5c844c0f1808fd7037750aebf4a94d
font_01_sfnt_off0000de2c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDE2C 10540 bytes
SHA-256: 230072cba404da30e2f5b1c31e52f1d6141f3e3fa4962d1059c01dd808d056a4

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