Malicious PDF — malware analysis report

Static analysis result for SHA-256 4f781a93a5b85a33…

MALICIOUS

PDF

83.4 KB Created: 2021-09-14 10:11:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 9e04ce3138300fd0970bffb170514410 SHA-1: b71bed9587b52c0b9ca8790a1e783df988c6c4ef SHA-256: 4f781a93a5b85a333273b2daf30f897948ffe032322a0fd03a8c82fd2129c77b
146 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The PDF document exhibits characteristics of a malicious lure, specifically instructing the user to install a remote support tool. The presence of numerous embedded URLs, many pointing to PDF files, suggests a link farm or distribution mechanism. The ML classifier strongly flagged this PDF as malicious, reinforcing the suspicious nature of the document's content and structure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9860

Heuristics 6

  • Password-protected archive handoff high SE_PASSWORD_ARCHIVE_LURE
    Document gives password instructions for an archive or attachment — often used to keep payloads encrypted until after gateway scanning
  • Remote-support tool lure high SE_REMOTE_SUPPORT_LURE
    Document instructs the user to install, open, or connect with a remote-support tool such as AnyDesk, TeamViewer, Quick Assist, or ScreenConnect — high-risk in an unsolicited document
  • 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://www.teppiche-waschen-hamburg.de/wp-content/plugins/formcraft/file-upload/server/content/files/1613e8bea80cf3---54033464838.pdf In PDF document text
    • http://www.ciesol.com/ckfinder/userfiles/files/47060818243.pdfIn PDF document text
    • http://wooshin.kr/uploaded/file/447659904613750bbf175d.pdfIn PDF document text
    • http://bhartiyambeohari.in/userfiles/file/nebunuxadiwunado.pdfIn PDF document text
    • http://fratellibeninca.com/images/file/52310645290.pdfIn PDF document text
    • http://aviatechinform.ru/sadm_files/55435689551.pdfIn PDF document text
    • http://otczenacts.com/media/files/timitamifo.pdfIn PDF document text
    • http://centronegozi.com/public/midovameriripowimazasisi.pdfIn PDF document text
    • https://hospvetcentral.pt/site/upload/file/gobanejibinaviman.pdfIn PDF document text
    • http://lamarchesainterita.be/lamarchesainterita/imgdb/news/files/78352019965.pdfIn PDF document text
    • http://yotlist.com/uniformkontakt/userfiles/image/files/mituradebogadi.pdfIn PDF document text
    • http://topimmigrationlawyer.org/ckfinder/userfiles/files/4705976990.pdfIn PDF document text
    • https://flomogroup.com/upload/files/67338210978.pdfIn PDF document text
    • http://sowa-architekci.pl/userfiles/files/misizo.pdfIn PDF document text
    • https://siliconautomation.com/userfiles/file/kilavimikomamepolozuxufik.pdfIn PDF document text
    • https://truongthanhco.vn/webroot/img/files/jipewibagipasoxizogolegof.pdfIn PDF document text
    • http://timavoshipsupply.it/userfiles/file/93944891265.pdfIn PDF document text
    • http://ncdesign.it/userfiles/files/29139878587.pdfIn PDF document text
    • http://stickerbarcode.com/file_media/file_image/file/jukopulusitukibux.pdfIn PDF document text
    • https://kingdomofgodmn.org/userfiles/files/jirotirimoxuzelevabuxoran.pdfIn PDF document text
    • http://captaincook.hu/userfiles/file/nasuguw.pdfIn PDF document text
    • http://vdi.vn/userfiles/file/fameneselamuvigoles.pdfIn PDF document text
    • http://roycraft.ca/userfiles/file/93935522975.pdfIn PDF document text
    • https://5udua.com/contents/files/buxuwedigizorewepidiro.pdfIn PDF document text
    • http://panel2conso.com/userfiles/file/65464258686.pdfIn PDF document text
    • http://engcaphone.com/_UploadFile/Images/file/72972040996.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/PmAiG5ZyT-k/uplcv?utm_term=nxt+remote+control+appPDF 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_off0000e3aa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE3AA 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000fbc1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFBC1 10356 bytes
SHA-256: a99169663e8ec76dbb39080650d83632837b88432495729f05599cccf29e9cef
font_02_sfnt_off00011325.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11325 17396 bytes
SHA-256: aab4437fab5e3b0c16becd9f20ece127cd8bd0cfcb39a96318e09cf444dd455b