Malicious PDF — malware analysis report

Static analysis result for SHA-256 81de443e299ca300…

MALICIOUS

PDF

75.8 KB Created: 2021-07-13 16:23:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-08-20
MD5: 8c1abc4e70f81b8cd3fbc6ce1002d66e SHA-1: cf2be11962d8f17446bd5877184ec6f11c2de62c SHA-256: 81de443e299ca300bb9e78d776d130d1380da6ab84262c8dc0f0968dc1ea8573
136 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file contains a high-severity heuristic firing for a redirector link, identified as a lure for free downloads and phishing. The ML classifier also flagged the PDF as malicious. While no scripts were extracted, the presence of a redirector URL strongly suggests a phishing attempt, likely delivered as a spearphishing attachment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.7390

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
  • 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://feedproxy.google.com/~r/sq/ugae/~3/UkUWPC8UKDU/square?utm_term=transform+to+standard+form PDF link annotation
    • https://static1.squarespace.com/static/60bf6c89a2b0b938881bcf91/t/60ec7d29e64ce537163430e5/1626111273879/castle_crashers_pink_knight.pdfIn PDF document text
    • https://static1.squarespace.com/static/60aac59fb7e9621e2f466549/t/60ed92c36bb85f4a8d88e97d/1626182339277/what_is_the_difference_between_inductive_and_deductive_method.pdfIn PDF document text
    • https://static1.squarespace.com/static/60aac52a97a1d73ddacfe14c/t/60ec9386831aaf5e928b9621/1626116998948/transition_css_multiple_properties.pdfIn PDF document text
    • https://static1.squarespace.com/static/60bf6c89a2b0b938881bcf91/t/60ed61396b40a9602c965518/1626169657122/35522381688.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_off0000ca46.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCA46 10208 bytes
SHA-256: a7e814fc05975bca120aeca545131dc2c0b0ee96fac94e47d1fcb247e2216733
font_01_sfnt_off0000e12a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE12A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f93c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF93C 16276 bytes
SHA-256: f2e11a955d6f1c11ce24d26969e9cbf5810101a440ac167b9ceb016b20713d54