Malicious PDF — malware analysis report

Static analysis result for SHA-256 a4d057765e2636c1…

MALICIOUS

PDF

74.9 KB Created: 2021-07-18 08:42:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-08-20
MD5: 99d4d401d068ba0fa3a9b1800171fed9 SHA-1: 4505a4edbd8e14dde97ce6c0c9f9c6bc976187ad SHA-256: a4d057765e2636c1da7eb408ca2deb75e0ccf440702350afdd43f40dbbb68a90
136 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by ClamAV as a phishing trojan and ML classifiers indicated maliciousness. A high-severity heuristic identified an image lure linking to an SEO redirector, which is a common phishing tactic. Although the document body is heavily obfuscated, the presence of a redirector URL suggests an attempt to lure the user to a malicious site.

Machine Learning

  • Nyx PDF Classifier malicious score 0.7788

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/NsX9ihectO0/square?utm_term=on+a+snowy+day PDF link annotation
    • https://static1.squarespace.com/static/60aac52a97a1d73ddacfe14c/t/60f0aa9a60a86f27d822f461/1626385050472/reported_speech_this_morning.pdfIn PDF document text
    • https://static1.squarespace.com/static/60aac59fb7e9621e2f466549/t/60f3b4e19c57c249393fe7d6/1626584289941/nijitoxunumetanefobeparo.pdfIn PDF document text
    • https://static1.squarespace.com/static/60bf6bff0d8d387fecc8b153/t/60f378956167905317dcab3c/1626568853394/mighty_man_of_god_scripture.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_off0000c7c1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC7C1 16180 bytes
SHA-256: fd1150596c4014492941812b40e35427c40d1377f8a596192e3b2c84a75fb37e
font_01_sfnt_off0000f1ca.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF1CA 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000109e1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x109E1 10000 bytes
SHA-256: ab3644342b3e7ea32ffa1740352536ac8e4168c16509c856585584043e2f3e1d