Malicious PDF — malware analysis report

Static analysis result for SHA-256 b57d5a7504f048eb…

MALICIOUS

PDF

77.8 KB Created: 2021-09-14 14:29:01 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 4c73205c89e163daa2df918cf7712bae SHA-1: dbbf627e5f0a8ce3ec30969090f58ee1a1d3f8c9 SHA-256: b57d5a7504f048eb12655e5d006d7c746e6c8725bd925646c6fbadac27b11b1e
66 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs, with one heuristic specifically identifying it as a link farm on disposable hosting. The ML classifier strongly indicates maliciousness. While no scripts were directly extracted, the presence of many external links suggests an attempt to redirect users to malicious sites, likely for phishing or malware delivery, aligning with spearphishing attachment tactics.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

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 https://cructi.ru/uplcv?utm_term=robbery+bob+free+coins
    • https://zippy-inc.com/app/webroot/userfiles/files/84036739485.pdf
    • http://www.hydro-tg.pro/upload/file/91355650906.pdf
    • http://dawahcity.com/userfiles/file/vuwawa.pdf
    • http://swotaweb.com/img/upload/file/52418487520.pdf
    • http://miroslaws.com/ckfinder/userfiles/files/vasebukelojamugakobite.pdf
    • https://tuvanthietke13-5.com/webroot/img/files/95025600193.pdf
    • https://hv2barrier.com/application/third_party/ckfinder/userfiles/files/32315992413.pdf
    • https://speculatio.in/ci/userfiles/files/xijomugi.pdf
    • http://findmealocalpainter.com/insurazon/admin/userfiles/file/vebarabi.pdf
    • http://asavn.vn/uploads/userfiles/files/gumelobogewovosixa.pdf
    • http://magnumprint.ru/upload/files/23102680944.pdf
    • http://xnucleus.com/members/member_images/files/18899687913.pdf
    • http://alexlunacoach.com/img/editor/file/4111079970.pdf
    • http://rubivina.com/Images_upload/files/dalapaduvilosobaviwa.pdf
    • https://alternativecarrepair.nl/userfiles/file/kobepogitesiwuf.pdf
    • https://servicepapik.ro/files/50657253216.pdf
    • http://nhakhoasaigonkimcuong.com/uploads/images/files/kosepekerifiwikozeko.pdf
    • 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_off0000cd94.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xCD94 16792 bytes
font_01_sfnt_off0000e5ab.bin
5071011ad91f6874b3758b7e09ed7db774b1e1a9ce20e1e61dfba26c9f855724
pdf-font-stream PDF embedded font (sfnt) at offset 0xE5AB 10320 bytes
font_02_sfnt_off0000fd17.bin
91aa7661f6fc879baf0094768e35ea26e2018c8fefbd679be1c68c828b589ef7
pdf-font-stream PDF embedded font (sfnt) at offset 0xFD17 17588 bytes