Malicious PDF — malware analysis report

Static analysis result for SHA-256 90f5fc184cddf1e5…

MALICIOUS

PDF

101.9 KB Created: 2021-07-16 08:59:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-13
MD5: 2b2c628c7bd769c332cd274bce648dff SHA-1: 646f5418de83a78cc125945807a6fc01734e1df7 SHA-256: 90f5fc184cddf1e5675968be2376afed94d9a2df84b1c0cc9c3bc34f4469d818
136 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as a malicious PDF by ClamAV and an ML classifier. Heuristics indicate it contains an external URI and an image lure linking to an SEO redirector, specifically 'https://inwebjor.ru/square?utm_term=research+marine+biologist'. This suggests a phishing attempt, likely delivered as a spearphishing attachment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.8151

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
  • Image lure linking to an SEO redirector (free-download phishing) high PDF_SEO_UTM_REDIRECTOR_LINK
    PDF embeds an image with little or no body text and a clickable link to a multi-word utm_term / FeedBurner-proxied SEO redirector — the 'free ebook / solution-manual / document download' phishing family that ranks for natural-language search queries and routes the user into a payload/redirect chain. The PDF carries no exploit; the risk is the linked destination. Flagged structurally (image lure + SEO redirector) so it does not depend on a ClamAV/ML signature, and regardless of how many filler text pages the lure carries.
  • 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://inwebjor.ru/square?utm_term=research+marine+biologist PDF link annotation
    • https://static1.squarespace.com/static/60bf6cad3a95e91b59aa2418/t/60e8cb43f28789513b644dfe/1625869123871/acnh_haunted_painting.pdfIn PDF document text
    • https://static1.squarespace.com/static/60bf6c89a2b0b938881bcf91/t/60e8624ed150f47af0a6cd94/1625842254457/my_dog_sleeps_with_her_tongue_out.pdfIn PDF document text
    • https://static1.squarespace.com/static/60aac59fb7e9621e2f466549/t/60e941f9e6bd1231e608f751/1625899513224/dance_classes_for_adults.pdfIn PDF document text
    • https://static1.squarespace.com/static/60bf6c89a2b0b938881bcf91/t/60f09ee02e6efd22d0313002/1626382048599/how_to_get_boots_shiny.pdfIn PDF document text
    • https://static1.squarespace.com/static/60aac59fb7e9621e2f466549/t/60ec8f473631fd4ab81701f8/1626115912124/noputolonumekujafaviji.pdfIn PDF document text
    • https://static1.squarespace.com/static/60bf6c89a2b0b938881bcf91/t/60ee7b37588fb5669518090d/1626241847597/biwagolunu.pdfIn PDF document text
    • https://static1.squarespace.com/static/60bf6bff0d8d387fecc8b153/t/60ede6414c056a31b81c0c13/1626203713867/37913878409.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://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00012cf8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12CF8 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0001450a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1450A 17612 bytes
SHA-256: 412131f5c13f093df21c9d098a86cafdbdf3511d9bbc480f9d74cfdfb6e02110
font_02_sfnt_off000172e0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x172E0 10860 bytes
SHA-256: 5ee9ec16ea38e86b6578ddaaf8b26ba25bd92d801bac597953f3cbccd77d75d1

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