Malicious PDF — malware analysis report

Static analysis result for SHA-256 a90ee860051e5d76…

MALICIOUS

PDF

76.0 KB Created: 2021-07-12 21:31:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-08-20
MD5: 90611d53bffec2d97c4969301b0fb148 SHA-1: 07e1a8f39ba34bf43a346d5509a49d042dca774c SHA-256: a90ee860051e5d7632720b9d0b7c473a9a949a3266c6d53de67dd52c53d5fff2
136 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was detected as malicious by ClamAV and an ML classifier, exhibiting characteristics of phishing. A high-severity heuristic identified an image lure linking to an SEO redirector, suggesting a phishing attempt. The embedded URL, while benign in reputation, is part of the lure mechanism.

Machine Learning

  • Nyx PDF Classifier malicious score 0.7703

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://feedproxy.google.com/~r/sq/ugae/~3/kVSxLQpkboc/square?utm_term=ringworm+is+a PDF link annotation
    • https://static1.squarespace.com/static/60aac5994c6b1805bc4acbdb/t/60e94733c4c1a734c5d81c8c/1625900851416/lucky_halo_2021_answers.pdfIn PDF document text
    • https://static1.squarespace.com/static/60bf69b23f3791685666e32d/t/60ec873c2de985067773eb7d/1626113852606/jenabaronozibagopoge.pdfIn PDF document text
    • https://static1.squarespace.com/static/60aac52a97a1d73ddacfe14c/t/60e906cf83ae0c490237fc8c/1625884367140/pazimojapurasogebexi.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_off0000cb61.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCB61 16216 bytes
SHA-256: 73dda00f5599c11516fffec2b931ffb4f60b44181f02d12619111c6b53293754
font_01_sfnt_off0000f54a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF54A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010d61.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10D61 10308 bytes
SHA-256: 9c41bff771a8f8b9e81fd7a8677bb4c6bfe18afd82cfec0a2cad911b901e6907