Malicious PDF — malware analysis report

Static analysis result for SHA-256 c921d3765eaccd89…

MALICIOUS

PDF

91.6 KB Created: 2021-09-16 23:15:56 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 6a55219b0eb8909ce9046c03326315b1 SHA-1: 65ce6b9b6d90b5cb3a433f553561b6ce0404c799 SHA-256: c921d3765eaccd8985a23d3596c9067c5e457aba0d62dbb7cc6c60cc0c074e4c
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 compromised CMS upload directories. The ML classifier strongly indicated maliciousness, and the structure suggests a link farm designed to manipulate search engine results or distribute further payloads. No scripts were extracted, but the presence of numerous external links is a primary indicator of malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9942

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://www.dentaltaxpros.com/wp-content/plugins/super-forms/uploads/php/files/d15ec6a2bbdd375e5d4a7216d6c4219e/88156699157.pdf
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612fdd8c08b25---27177803956.pdf
    • https://maidintown.co.uk/wp-content/plugins/super-forms/uploads/php/files/44ebb2aa5a388861db9945cdd958dfcc/padifu.pdf
    • http://energo-winstal.pl/userfiles/file/43776649348.pdf
    • http://jcpingie.be/public/files/julabubolenipej.pdf
    • http://iamsoldierfit.com/wp-content/plugins/formcraft/file-upload/server/content/files/16130bd9cbe5c0---gosabanunekugiwaseditaful.pdf
    • http://mnwebdesign.dk/userfiles/file/6215820118.pdf
    • https://granitnet.hu/editor_up/zukatoroguvup.pdf
    • https://piti.leaddeehub.com/userfiles/files/87168695495.pdf
    • http://gomientrung.vn/uploads/image/files/purawul.pdf
    • http://www.temaricerca.com/entry2013new/admindia/ckfinder/userfiles/files/nikefa.pdf
    • http://bonfiremadigan.com/uploads/fckeditor/file/tusoz.pdf
    • http://southportrubbish.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613e3281a5b9d---25555423141.pdf
    • http://neodev.space/wp-content/plugins/formcraft/file-upload/server/content/files/16136dabe2d259---3608595963.pdf
    • https://illustrations.noche.fr/images/files/22048608333.pdf
    • http://gyermekhaz.hu/Content/site_images/files/45998445192.pdf
    • http://progettocecinacuore.it/writable/public/userfiles/file/1843802376.pdf
    • http://cw-cut.com/uploads/file/vimamuzasudiwubafalugir.pdf
    • http://jca-t.com/fck_image/file/vulebusizememobuzezo.pdf
    • http://chinazzjx.com/d/files/76241932788.pdf
    • http://www.gamylai.vn/uploads/files/9696732345.pdf
    • https://avukatwebsitesi.trakyasoft.com/upload/files/lunij.pdf
    • http://goldcoil.com/uploadfiles/files/pusujizidolag.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/fzgW7-mxBc0/uplcv?utm_term=best+way+to+spoof+pokemon+go+android
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000fedd.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xFEDD 16792 bytes
font_01_sfnt_off000116ef.bin
1f57b846df299c28f3c2c812bae1ce16f224bf13c303077325fe0ce5b17caacb
pdf-font-stream PDF embedded font (sfnt) at offset 0x116EF 18344 bytes
font_02_sfnt_off000146d1.bin
3b30dfa07a860079a6e19e1bfdc11287ea6aa995007fc33ad355e0bdbba00d6c
pdf-font-stream PDF embedded font (sfnt) at offset 0x146D1 11140 bytes