Malicious PDF — malware analysis report

Static analysis result for SHA-256 13f9820245d6bc0e…

MALICIOUS

PDF

82.8 KB Created: 2021-09-11 14:44:37 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-27
MD5: 306adc7eedaa8e28c8ef35d17eaaafff SHA-1: bbad7f0047d88c06c85f8e39753da904a293278f SHA-256: 13f9820245d6bc0e0e9542037ad04ff93d43ac333e6cbe8c5c190dbeeb9294a8
66 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF was identified as malicious by an ML classifier and contains numerous embedded URLs, many of which point to other PDF files. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' indicates a pattern of link farming on disposable hosting, suggesting a non-standard use of the PDF. While no scripts were explicitly extracted, the nature of the embedded URLs and the link farm heuristic suggest a potential for malicious content delivery or SEO manipulation.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9917

Heuristics 4

  • 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://classtool.info/upload/files/gapuvojolidatemaporiwumal.pdf In PDF document text
    • https://cytairtool.com/test/userfiles/file/20210902_29eed.pdfIn PDF document text
    • http://eegbiofeedback-leszno.pl/userfiles/file/fubivuxovewufi.pdfIn PDF document text
    • http://dkmmotor.com/files/userfiles/file/10241951251.pdfIn PDF document text
    • http://www.pattyn360.com/upload/forum/files/67168962400.pdfIn PDF document text
    • http://yongqingtech.com/d/files/61746224335.pdfIn PDF document text
    • https://epgeptech.hu/ckfinder/userfiles/files/xegako.pdfIn PDF document text
    • http://www.elstar.ru/uploads/files/nenojovoruzisipevirusefi.pdfIn PDF document text
    • https://profix.fr/ckfinder/userfiles/files/dodaguvozakazowizaguk.pdfIn PDF document text
    • http://www.icf-plant.com/files/file/76137982007.pdfIn PDF document text
    • http://ellissi.org/userfiles/files/zigiwepifawutamalowumeg.pdfIn PDF document text
    • http://auxerretv.com/content/public/file/30018082764.pdfIn PDF document text
    • http://ansing.nl/userfiles/file/48526589105.pdfIn PDF document text
    • http://scard.vn/app/webroot/uploads/files/leladiluk.pdfIn PDF document text
    • https://krygina40.ru/UserFiles/File/nofaxogajilerakujune.pdfIn PDF document text
    • https://yuanfuconstruction.com/ckfinder/upload/files/88023644915.pdfIn PDF document text
    • http://happyland-nsk.net/ckfinder/userfiles/files/70188088989.pdfIn PDF document text
    • http://smsalumni1971.com/apadmin/uploads/userfiles/files/51840030800.pdfIn PDF document text
    • http://emeat.ru/var/files/79824065012.pdfIn PDF document text
    • https://dom4m.com/userfiles/files/53822889518.pdfIn PDF document text
    • https://santa.sg/images/users/00000000/files/zarosiwux.pdfIn PDF document text
    • https://mediaskills.rs/files/zevunugerudanamot.pdfIn PDF document text
    • http://www.supair-lux.hu/ckfinder/userfiles/files/75614789637.pdfIn PDF document text
    • http://artattack-concerts.de/files/file/tigomiretevekuxor.pdfIn PDF document text
    • https://grootformaatspandoeken.nl/userfiles/file/rixozo.pdfIn PDF document text
    • http://www.neoneophytou.com/ckfinder/userfiles/files/5330139518.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/LPIa9PGmDLg/uplcv?utm_term=wild+blood+apk+downloadPDF link annotation
    • 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_off0000dfae.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDFAE 10196 bytes
SHA-256: 80ef4b443bb1b2edee42f765b8ffa8f38366e2f26c40c69ffb8df53c95bf2573
font_01_sfnt_off0000f655.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF655 17900 bytes
SHA-256: 334c7142c75d069b53bcd74186c58a37a3d2d24889ab5b605838e10acdad1cea
font_02_sfnt_off0001252c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1252C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1