Malicious PDF — malware analysis report

Static analysis result for SHA-256 a10844c190ee5ae6…

MALICIOUS

PDF

86.6 KB Created: 2021-09-15 11:45:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-20
MD5: 8c382d85fd464ecd0f7dcd0dac23925b SHA-1: 80da07a466322770b649dd46c39f493c9f8e5948 SHA-256: a10844c190ee5ae6da56466b21bf2534c02c537917a98a1548d047e5c792c95b
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains a large number of links, many of which point to compromised CMS upload directories or disposable hosting. The ML classifier strongly indicated maliciousness. The primary attack pattern observed is the use of a link farm to redirect users to potentially malicious content hosted on various external sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9976

Heuristics 5

  • 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 https://kolodezrus.ru/wp-content/plugins/super-forms/uploads/php/files/fc9cdaef88158de6744eed4b513f428f/pewiza.pdf In PDF document text
    • https://seroinstitute.com/wp-content/plugins/super-forms/uploads/php/files/da30d4d5fedced20df43abedf042eb32/pupefokasoravuz.pdfIn PDF document text
    • http://sahamit.net/userfiles/file/31524150959.pdfIn PDF document text
    • https://reha.bg/content/upload/file/desopop.pdfIn PDF document text
    • http://naoshima-habitant.com/images/blog/file/jubonaberoxikebosawur.pdfIn PDF document text
    • https://supportsystemsvainc.com/home/ssvi/public_html/ckfinder/userfiles/files/verogesal.pdfIn PDF document text
    • http://fapannimario.it/userfiles/files/jerilutij.pdfIn PDF document text
    • https://muzeumkonstancina.pl/attachments/file/86509946394.pdfIn PDF document text
    • https://viboot.com/ckfinder/userfiles/files/84112759061.pdfIn PDF document text
    • http://needychild.org/ckfinder/userfiles/files/13425883588.pdfIn PDF document text
    • https://www.golaw.net/wp-content/plugins/formcraft/file-upload/server/content/files/1614170522928e---nomareteruwozut.pdfIn PDF document text
    • http://drvision.org/wp-content/plugins/formcraft/file-upload/server/content/files/1613babdc6e982---nokatuxoxowo.pdfIn PDF document text
    • https://wietsevoermans.nl/ckfinder/userfiles/files/domutowusu.pdfIn PDF document text
    • https://agrotehholding.ru/wp-content/plugins/super-forms/uploads/php/files/46aea3b4f294da4a8b4d08b085bba59f/28446672402.pdfIn PDF document text
    • http://brbud.pl/userfiles/file/19743987850.pdfIn PDF document text
    • http://immobilieninvestors.de/userfiles/file/75665088569.pdfIn PDF document text
    • http://sjzhtchem.com/upload/files/xaluxovewuwegilivobabijef.pdfIn PDF document text
    • http://www.maoles.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612fe32480d0c---55881519200.pdfIn PDF document text
    • http://daegyung.kr/userfiles/file/20210910115332.pdfIn PDF document text
    • https://fresh-cherries.com/ckfinder/userfiles/files/37205340006.pdfIn PDF document text
    • http://condominiobrisasdelnorte.com/userfiles/file/43153414065.pdfIn PDF document text
    • https://inunekocp.jp/mailmagazine/upload/files/16680615977.pdfIn PDF document text
    • https://doan295doson.vn/namthuan/images/news/files/botad.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/YTWXjIUwRh0/uplcv?utm_term=data+link+layer+computer+networkPDF 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_off0000ea1e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEA1E 10760 bytes
SHA-256: 11e5f68c20aa386fa252be93080a820daeb7eb02e5831393d0c4d96cdc6b2df3
font_01_sfnt_off000102e6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x102E6 19040 bytes
SHA-256: 2cba858d7099dfd4f9cfb39a9bcb05ce4915e03535eac8a796a3c3ec96baeee4
font_02_sfnt_off0001346d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1346D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1