Malicious PDF — malware analysis report

Static analysis result for SHA-256 21acaa052866e732…

MALICIOUS

PDF

71.4 KB Created: 2021-09-25 13:57:54 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 158c246e0970542f9c4e9243b349bbd5 SHA-1: 2ebd1b71e74559d9490a619f6340e2648df6b093 SHA-256: 21acaa052866e7324509f57e70f5d381f36db7c0801c13aaafc4391cb51d39f6
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains numerous embedded URLs pointing to compromised CMS uploads and disposable hosting domains, indicating a link farm or redirection scheme. The ML classifier strongly flagged this PDF as malicious. While no scripts were extracted, the extensive use of external links suggests a potential for downloading further payloads or leading users to phishing sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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://pistant.ru/uplcv?utm_term=poco+x3+pro+8gb+antutu+score PDF link annotation
    • http://getem.pl/files/file/63808733508.pdfIn PDF document text
    • https://akonis.ch/userfiles/files/wezowudabonelamuzadul.pdfIn PDF document text
    • https://xn--80aaa1arbfjoe3bzh.xn--p1ai/data/files/88773430500.pdfIn PDF document text
    • https://korzayithalat.com/spot/admin/fckeditor/userfiles/file/nulinudogujuvevot.pdfIn PDF document text
    • https://izometal.net/mm/file/12947927931.pdfIn PDF document text
    • http://beautifulmoda.com/userfiles/files/difusotisukemetafulofixox.pdfIn PDF document text
    • http://braintradingbcn.com/wp-content/plugins/super-forms/uploads/php/files/ca020abaf87eff775f5069c972b726d8/muxipeg.pdfIn PDF document text
    • http://oio.cn/uploadfiles/files/ligoluduxubifosole.pdfIn PDF document text
    • http://khmim.com/ckfinder/userfiles/files/38369968309.pdfIn PDF document text
    • http://www.dfdtrading.sk/ckfinder/userfiles/files/mawavoranaf.pdfIn PDF document text
    • http://mikomisushiwc.com/uploads/files/15170021485.pdfIn PDF document text
    • http://karmakonnect.org/DrumiBhatt/karmakonnect.org/Final/ckeditorimage/files/77324298284.pdfIn PDF document text
    • https://daqing-jewelry.com/uploads/files/202109111145351151.pdfIn PDF document text
    • http://www.neslihanonur.com/wp-content/plugins/super-forms/uploads/php/files/f2547539b2bf430d35bde2a1fe9e6488/22101424636.pdfIn PDF document text
    • http://counterreaction.net/wp-content/plugins/formcraft/file-upload/server/content/files/16144f50fbe157---28065225494.pdfIn PDF document text
    • http://slhospital.com/upload/fckeditor/file/vasenuperarejak.pdfIn PDF document text
    • http://baracenter.be/userfiles/file/22276380651.pdfIn PDF document text
    • http://burmeseburmilla-allevamento.com/userfiles/files/musabodopagevoge.pdfIn PDF document text
    • http://pc580.cn/upload_fck/file/2021-9-6/20210906192649203508.pdfIn PDF document text
    • https://alternativi.brtim.com/uploads/wysiwyg/files/nopubokovuradili.pdfIn PDF document text
    • https://rosettes.it/userfiles/file/83141820986.pdfIn PDF document text
    • http://auto-spec.ca/fck/file/jojibosekuvivu.pdfIn PDF document text
    • http://2016.letnifestiwal.pl/ckfinder/userfiles/files/vomunetukategovejuse.pdfIn PDF document text
    • https://aldea.work/wp-content/plugins/super-forms/uploads/php/files/f1910513b6ce01a36a9b499c46f6cfca/kotidexi.pdfIn PDF document text
    • 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_off0000b40f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB40F 11136 bytes
SHA-256: 277116432a043c5043dff5db4325f6ee700941b8b0aa9e9362899731a2068a9c
font_01_sfnt_off0000ce1c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCE1C 15564 bytes
SHA-256: 17a9b9d21b149e53a70c1d82bddf0bb6458aeb45855159f337904e061418d054
font_02_sfnt_off0000f5d0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF5D0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1