Malicious PDF — malware analysis report

Static analysis result for SHA-256 8f51d793322b2ce6…

MALICIOUS

PDF

95.4 KB Created: 2021-07-13 18:50:12 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-08-25
MD5: 9d906ecd3345ad7c51321da4fb85d90a SHA-1: 328306e68812ca4a7185699bc7dc6e0bcaf85aaa SHA-256: 8f51d793322b2ce6ccd44f004b5c8b9715ffee58425883fe0737196187ebcf87
136 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF document contains a heuristic firing indicating it's a phishing lure using an SEO redirector. The embedded URL, 'https://philabc.ru/square?utm_term=sample+recommendation+letter+for+student+from+professor', is identified as the primary malicious link. ClamAV also detected this file as 'Pdf.Phishing.Trojan'. No scripts were extracted, but the overall structure and URL suggest a phishing attack.

Machine Learning

  • Nyx PDF Classifier malicious score 0.8172

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://philabc.ru/square?utm_term=sample+recommendation+letter+for+student+from+professor PDF link annotation
    • https://static1.squarespace.com/static/60aac5994c6b1805bc4acbdb/t/60e952c283ae0c49023a9377/1625903810738/gafevesufagubuwolodigir.pdfIn PDF document text
    • https://static1.squarespace.com/static/60bf6bff0d8d387fecc8b153/t/60e8c74a73083775092def4a/1625868107103/cortisol_is_low.pdfIn PDF document text
    • https://static1.squarespace.com/static/60bf6c89a2b0b938881bcf91/t/60e8b23a1c98860cff5be253/1625862714792/pizemukaziwedanexodimozu.pdfIn PDF document text
    • https://static1.squarespace.com/static/60aac52a97a1d73ddacfe14c/t/60ec927758d864752e02481e/1626116727987/the_word_pollution_is_derived_from_latin_word.pdfIn PDF document text
    • https://static1.squarespace.com/static/60aac5994c6b1805bc4acbdb/t/60e7e32dbab062161338c391/1625809709251/sample_solicitation_letter_for_donations_tagalog.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_off0001149a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1149A 16716 bytes
SHA-256: 4c28b3b90c563de5974aae34c90196a5d6e990f4946472fea82a0a489611ee24
font_01_sfnt_off00013fd6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13FD6 10956 bytes
SHA-256: 40de6ad451f4b3ddbc17ad555db3de02c408c0cb6aa0134a0fa60b5e3be880dd
font_02_sfnt_off00015932.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15932 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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