Malicious PDF — malware analysis report

Static analysis result for SHA-256 c31aca2d9f3522bb…

MALICIOUS

PDF

91.9 KB Created: 2021-07-12 21:10:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-08-20
MD5: 843837282d876df65ecf9ed8556395a9 SHA-1: cf988138a778f3990cbd831fc5f5f774fec69c88 SHA-256: c31aca2d9f3522bb2bbe11b37e1e10abbe0600b6881b6f6aa3909fb85d95072b
84 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains heuristics indicating it is a fake invoice lure, designed to entice users to click on an external link. While the primary link identified is confirmed benign, the overall pattern suggests a phishing or malware distribution attempt. No scripts were extracted, limiting further analysis of the payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.5959

Heuristics 5

  • 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.
  • Fake invoice / payment lure low SE_INVOICE_LURE
    Document contains invoice or payment language paired with an action verb — useful context when combined with link, macro, or attachment indicators
  • 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/razvivatel/yapz/~3/0YvHz_IItD0/square?utm_term=prominent+composers+of+romantic+period PDF link annotation
    • https://static1.squarespace.com/static/60bf6c89a2b0b938881bcf91/t/60e965472c5c2f6215caedc5/1625908552008/3800523197.pdfIn PDF document text
    • https://static1.squarespace.com/static/60aac4e0d5abe22cec5c4b22/t/60e7a9a78ad60325f0c397cf/1625794983452/19871378482.pdfIn PDF document text
    • https://static1.squarespace.com/static/60bf6c89a2b0b938881bcf91/t/60ec857ce94d7a30e0556212/1626113404866/50341083720.pdfIn PDF document text
    • https://static1.squarespace.com/static/60bf6cad3a95e91b59aa2418/t/60ec71bca3e9df788e6b88b0/1626108348139/pericardial_effusion_life_expectancy.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_off0001035f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1035F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00011b71.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11B71 18120 bytes
SHA-256: a44b6da012e7ed2f5e970e6432767a326e1e9dc36add1a6c5e789245f269afbb
font_02_sfnt_off00014b5e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14B5E 10736 bytes
SHA-256: 4e02afab00e7e2db457080f37a5e46c6bc63a41127692fa3cc68479d2c2801ec