Malicious PDF — malware analysis report

Static analysis result for SHA-256 a9677551e7ab55f5…

MALICIOUS

PDF

88.8 KB Created: 2021-10-10 08:02:33 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 94463fc46fb7bff8be7dbcefa0ae770e SHA-1: 661db2f30870a843811a105fd8dc4a305bd26506 SHA-256: a9677551e7ab55f5045033269c9fbfb8912d74760efb3db2b895b0b42355919b
96 Risk Score

Malware Insights

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

The PDF contains a large number of embedded URLs, many of which point to PDF files hosted on compromised websites. This behavior is indicative of a link farm, potentially used for SEO manipulation or to distribute further malicious content. The ML classifier strongly flagged this PDF as malicious, supporting the assessment of a malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9948

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://husvagnsexpo.se/wp-content/plugins/formcraft/file-upload/server/content/files/1613b245f5ddbe---86080588302.pdf In PDF document text
    • http://tpdw.pl/userfiles/file/45814433904.pdfIn PDF document text
    • https://ciiinnovationsummit.com/ci/userfiles/files/gadofanuj.pdfIn PDF document text
    • http://goldcoil.com/uploadfiles/files/77735083853.pdfIn PDF document text
    • http://videofilm-tv.ru/content/File/93703702145.pdfIn PDF document text
    • https://dom4m.com/userfiles/files/85660191968.pdfIn PDF document text
    • http://marasintl.com/public/ckfinderuploads/files/50858810666.pdfIn PDF document text
    • http://akademibt.com/resimler/files/gegolafanutakelibeximalo.pdfIn PDF document text
    • https://inprovituruguay.com/ckfinder/userfiles/files/wimarorirojugonaxokatisu.pdfIn PDF document text
    • https://jungleflightchiangmai.jungle-flight.com/Uploads/files/jumikufi.pdfIn PDF document text
    • http://ferien-in-zahren.de/images/file/52279333526.pdfIn PDF document text
    • https://www.nvsrolko.org/ckfinder/userfiles/files/71229740541.pdfIn PDF document text
    • http://bassonconsulting.mc/userfiles/file/kidepenegetovejafenoge.pdfIn PDF document text
    • http://drinkandshrink.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1616222a7f1177---gizeka.pdfIn PDF document text
    • https://www.sacproblemleri.com/wp-content/plugins/formcraft/file-upload/server/content/files/16131921145cd7---684988969.pdfIn PDF document text
    • http://dfwarbitrator.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/lenov.pdfIn PDF document text
    • https://aryaayur.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613af3c55eec2---polanasijorabuzuxi.pdfIn PDF document text
    • http://lagostena.it/userfiles/files/suvit.pdfIn PDF document text
    • http://dreamsurgeryen.net/ckupload/files/23019046824.pdfIn PDF document text
    • http://stjconsulting.it/userfiles/files/45793017583.pdfIn PDF document text
    • http://sgrappresentanze.eu/userfiles/files/47030301368.pdfIn PDF document text
    • http://yuhenganquan.com/userfiles/file/20210908030457_1024701757.pdfIn PDF document text
    • http://themultifold.com/wp-content/plugins/super-forms/uploads/php/files/taoa38804uqfjsh0ggbfovf043/63814012460.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/FevRqgeaUVY/uplcv?utm_term=just+like+water+lauryn+hillPDF 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_off0000eedf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEEDF 10468 bytes
SHA-256: d7d9c2f4cbc4bb0ea090c1ecd45705bdbf975663d0a0c18c0e4be23ad924a5a7
font_01_sfnt_off000106b3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x106B3 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011ec5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11EC5 21236 bytes
SHA-256: 47f6ddd7bcfba8e4162f2277b3554a549f6da0e1d53de203ca33690f377fe47c