Malicious PDF — malware analysis report

Static analysis result for SHA-256 5c55216c1bd0e1c8…

MALICIOUS

PDF

81.8 KB Created: 2021-09-07 17:05:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-01
MD5: 097656e250652d2a342934ff74af0f8d SHA-1: 2c52911ce02ddfa64383414c4b1d736056d2ae56 SHA-256: 5c55216c1bd0e1c85eb3ccc4a34bcd47f0882059750cb2459b0aca5440493dc9
136 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF document was flagged as malicious by an ML classifier. It uses a LOLBin command-execution lure. The file embeds a large number of external links characteristic of an SEO link farm, many hosted on compromised CMS upload directories. Specific URLs and indicators for this sample are listed in the indicators section.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9952

Heuristics 6

  • LOLBin token sequence in document text high SE_LOLBIN_RUN_COMMAND
    Extracted document text contains a Windows script/execution tool name (PowerShell, mshta, cmd, rundll32, regsvr32, …) within 220 characters of a dangerous flag, command verb, or URL. This is a visible 'run this' instruction in HTML/PDF/RTF lure bodies, or — in macro-laden Office files — the macro's own string-pool entries appearing adjacent in extracted text.
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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://www.makattakasinti.com/wp-content/plugins/formcraft/file-upload/server/content/files/16077b01b64f39---83030844.pdf In PDF document text
    • http://curry-box-deluxe.de/userfiles/file/dusokumapituzogijofapin.pdfIn PDF document text
    • http://charmingcurls.se/upload/file/95154109114.pdfIn PDF document text
    • https://perfecthospitals.org/FCKeditor/file/munavubamefaligup.pdfIn PDF document text
    • http://abwjefferson.com/uploads/files/65605327556.pdfIn macro / runtime command snippet
    • https://www.chartsunlimited.com.ph/wp-content/plugins/formcraft/file-upload/server/content/files/1607c5c54d17d1---59748686957.pdfIn PDF document text
    • http://amandamaitland.com/images/file/6663785939.pdfIn PDF document text
    • http://voszveszprem.hu/_user/file/fowidebumifolevomagipum.pdfIn PDF document text
    • http://aksaxena.com/bpms/includes/fckeditor_uploads/userfiles/file/36663780924.pdfIn PDF document text
    • http://www.investinwielkopolska.pl/application/lib/ckfinder/userfiles/files/vapezovixidaruzujalesafog.pdfIn PDF document text
    • http://self119.net/upload/userfiles/2021/07/files/210728003147.pdfIn PDF document text
    • http://www.ecostroyservis.ru/File/26534295390.pdfIn PDF document text
    • http://problemconsulting.com/img/download/files/gezuzidevutalim.pdfIn PDF document text
    • http://lifemartrealestateconnect.com/wp-content/plugins/super-forms/uploads/php/files/nkicq8ttu765nl306nkq3angr3/6948223726.pdfIn PDF document text
    • https://brusroom.com/wp-content/plugins/super-forms/uploads/php/files/81c31f56882d21f117d7b4bd4f496ddd/worodepotilelewexoxajon.pdfIn PDF document text
    • http://ctyrkolky-gamax.cz/data/dokumenty/99802939740.pdfIn PDF document text
    • http://tion.hu/upload/file/kasugelodapujakutexubimar.pdfIn PDF document text
    • https://klingende-zeder.de/wp-content/plugins/formcraft/file-upload/server/content/files/160702f833083d---38367564502.pdfIn PDF document text
    • https://www.quatainvestimentos.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16089c73973640---pojepos.pdfIn PDF document text
    • http://ppfi-online.com/userfiles/file/zidavopiva.pdfIn PDF document text
    • https://jmcoverseaspvtltd.com/uploads/files/nuteja.pdfIn PDF document text
    • http://www.sunarmisir.com.tr/wp-content/plugins/super-forms/uploads/php/files/ta2mkefmvjiq7g2ubo8rnbm713/79031631794.pdfIn PDF document text
    • http://pogservice.ru/userfiles/file/nupagelisodikaji.pdfIn PDF document text
    • https://perfecthospitalIn macro / runtime command snippet
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/ngfLrbzwjls/uplcv?utm_term=mac+preview+ocr+pdfPDF link annotation
    • 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_off0000de74.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDE74 19396 bytes
SHA-256: 5a4381f90e05800f537f346619a0a0a0b650e9550fdfb03a5206fb1f026c3b16
font_01_sfnt_off000110e1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x110E1 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000128f8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x128F8 10344 bytes
SHA-256: 200755da559c773f2576302c925cbed68a80952bad14d48a87f658122cf469e3