Malicious PDF — malware analysis report

Static analysis result for SHA-256 90b2c86ee7162797…

MALICIOUS

PDF

76.6 KB Created: 2021-07-21 08:47:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-08-20
MD5: 155f07f97800a51f490eb66974536e11 SHA-1: ada1b395503b1c9ed074ca9a45837474b801e095 SHA-256: 90b2c86ee7162797e449b877337a753c00d0f716dafaf6828fea940181f1d8b1
216 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF file was detected as malicious by ClamAV and an ML classifier. Heuristics indicate social engineering tactics, specifically a 'ClickFix' attack and a 'Browser installation lure', suggesting the document aims to trick the user into executing malicious code or installing unwanted software. The embedded URL, while flagged as benign, is part of the lure. The document body is heavily obfuscated, preventing a clear understanding of its direct content, but the heuristics strongly point towards a phishing or malware delivery attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.7604

Heuristics 7

  • 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.
  • ClickFix social engineering attack high SE_CLICKFIX
    Document instructs the user to press Win+R or paste a command into a terminal — consistent with ClickFix attacks that bypass macro restrictions by tricking users into running malicious commands directly
  • Browser extension / update installation lure high SE_BROWSER_INSTALL_LURE
    Document tells the user to install a browser extension, plugin, viewer, or browser update to view content — a common social-engineering path for credential theft and malware installation
  • 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/AnJPYMJXbyQ/square?utm_term=class+12+computer+book+pdf+download PDF link annotation
    • https://static1.squarespace.com/static/60aac52a97a1d73ddacfe14c/t/60edf23836d5170423626ca6/1626206776964/history_of_europe_1789_to_1919.pdfIn PDF document text
    • https://static1.squarespace.com/static/60aac4dd19f082755c4e5c69/t/60edde37cc8e436e46655822/1626201655096/83549932003.pdfIn PDF document text
    • https://static1.squarespace.com/static/60aac59fb7e9621e2f466549/t/60f08edc78de530e1d42498b/1626377948599/208889352.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_off0000c9f1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC9F1 16172 bytes
SHA-256: 0cb2cb3ee98a3e5de774987bd58a1f7394b2ab87b2fa54521930fbd7901ba01b
font_01_sfnt_off0000f3cf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF3CF 11312 bytes
SHA-256: 3f7d03063a6d70322fb03b865e1fc8cce54eb6c52aa788dc1f85b4e0b5d9c796
font_02_sfnt_off00010e66.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10E66 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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