Malicious PDF — malware analysis report

Static analysis result for SHA-256 24af3bbc576cfe84…

MALICIOUS

PDF

82.3 KB Created: 2021-09-19 02:19:08 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 3cbcc4d4fecf4405462418f968bbf181 SHA-1: a2637285daf53b83cf8e8cc787912821ed5973da SHA-256: 24af3bbc576cfe84ddb994032a5e0f9a8af7f61b16d71bef152b30ff5fbe18dd
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF sample was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs, many of which point to disposable domains and appear to form a link farm, a common tactic for phishing or distributing further malware. The presence of PDF_SEO_DISPOSABLE_LINK_FARM heuristic further supports this. No scripts were extracted, but the overall structure and heuristics indicate a malicious intent to redirect users to potentially harmful sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9955

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
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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 http://solarissoft.com/img/userfiles/files/80380969258.pdf
    • http://infinivideo.hu/sites/infinivideo/files/niwadazexotexokib.pdf
    • http://usa-ex.com/images/blog/file/zasozilimezimimawunolu.pdf
    • http://getem.pl/files/file/zigir.pdf
    • https://nevjegyzek.eu/uploads/file/9897723247.pdf
    • http://tomekorea.com/userData/board/file/92987657359.pdf
    • https://leifs-auto.dk/images/file/kukodofo.pdf
    • https://longhoang.vn/upload/files/vajenope.pdf
    • https://shibbirs.com/media/files/53071132632.pdf
    • http://ipceurope.be/assets/file/gegipisukezonesadap.pdf
    • http://auto4-spb.ru/public/images/ckfinder/files/kodufawajovaduwemuvaxivef.pdf
    • https://millersexpress.com/userfiles/file/21535513876.pdf
    • http://byty-pardubice.eu/UserFiles/File/guraxazej.pdf
    • https://aurorabersinar2.com/contents/files/vebudorunofapifose.pdf
    • https://shinko-tw.com/UserFiles/file/fikezuzizujufora.pdf
    • http://ohxto.com/uploaded_files/userfiles/files/64279771481.pdf
    • https://planningpvedh.nl/ckfinder/userfiles/files/80680019905.pdf
    • https://deepex.hu/hirek/files/pofapakufemozutuxa.pdf
    • https://callmarkinvestments.com/callmark/files/68225985356.pdf
    • http://luyenthidhcanhsat.com/Images_upload/files/veregubamazam.pdf
    • https://investincarpathians.eu/app/webroot/media/files/rupanusijefekuremibenevem.pdf
    • https://xtremefitness.com.au/application/third_party/ckfinder/userfiles/files/18181840413.pdf
    • https://camping-du-lac-dijon.com/userfiles/fichiers/bibogasov.pdf
    • http://ofitecnic.es/files.ofitecnic/fck_up/file/43444209922.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/1KS0DP0cxss/uplcv?utm_term=convert+radians+to+minutes
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d8f8.bin
8b1657df17ecd2625d72b43d773079e89d8008341a605ed1be4d09d8ef59b361		 pdf-font-stream PDF embedded font (sfnt) at offset 0xD8F8 10560 bytes
font_01_sfnt_off0000f11f.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1		 pdf-font-stream PDF embedded font (sfnt) at offset 0xF11F 16792 bytes
font_02_sfnt_off00010931.bin
a867445d7466a4e34f9414580f693624a09e00bec3a75dcc8a2c0446756c62db		 pdf-font-stream PDF embedded font (sfnt) at offset 0x10931 19304 bytes

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