Malicious PDF — malware analysis report

Static analysis result for SHA-256 c51437d1f94b13c0…

MALICIOUS

PDF

82.2 KB Created: 2021-09-09 13:09:09 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 551dcd39d15b00db1e8c2157f622e6ed SHA-1: 9b2e86d09b22de2bcc540974de4eb9a6ea70a9c1 SHA-256: c51437d1f94b13c0474969d68e15116ce93bbd1c6cfcef99eaa5bb94de553cca
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF file was flagged by an ML classifier as malicious. Heuristics indicate it contains a link farm pointing to compromised WordPress upload storage, suggesting an attempt to host malicious files or redirect users. The presence of multiple URLs on potentially compromised domains supports this attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9960

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://saftanton.dk/wp-content/plugins/formcraft/file-upload/server/content/files/16139845771319---vixugodatevofadesitulo.pdf In PDF document text
    • http://swvocal.com/data/se2/file/xujaxegamolesowu.pdfIn PDF document text
    • http://stroykap.com/application/views/stroykap/userfiles/file/34428027316.pdfIn PDF document text
    • http://oishisushigd.com/uploads/files/bisix.pdfIn PDF document text
    • http://cgemfoco.com.br/ckfinder/userfiles/files/86810445077.pdfIn PDF document text
    • https://cvzona.lt/resources/img/files/78840572786.pdfIn PDF document text
    • https://palet-school.com/files/files/81315005720.pdfIn PDF document text
    • https://www.hs-hofgastein.salzburg.at/ckfinder/userfiles/files/bekoguxifuxu.pdfIn PDF document text
    • http://jncs.kr/page_data/file/20210904034634.pdfIn PDF document text
    • http://candientushinko.com/images/file/novedo.pdfIn PDF document text
    • http://grapes4u.ca/sites/all/sites/grapes4u.ca/files/rovifopomek.pdfIn PDF document text
    • http://puebloexec.com/userfiles/file/25364977481.pdfIn PDF document text
    • https://macauroommate.com/ckfinder/userfiles/files/49316026963.pdfIn PDF document text
    • http://www.moteco.ro/wp-content/plugins/formcraft/file-upload/server/content/files/16134c0f0c4058---zepilapowosuluzepilesuji.pdfIn PDF document text
    • http://kanizsakran.hu/userfiles/file/58596685336.pdfIn PDF document text
    • http://maraulsan.com/ckfinder/userfiles/files/kirinilezarunoped.pdfIn PDF document text
    • https://eqonetech.com/upload/userfiles/files/nugar.pdfIn PDF document text
    • http://cabanagarden.hu/editor_up/zozirufakixasora.pdfIn PDF document text
    • https://www.carlosfunes.es/wp-content/plugins/formcraft/file-upload/server/content/files/16130c9112df1b---58951443526.pdfIn PDF document text
    • https://hotelristorantenovecento.it/wp-content/plugins/super-forms/uploads/php/files/e99a1b34ddea2636e68a0d7100c2bdcd/wamokoma.pdfIn PDF document text
    • http://elcolono.net/userfiles/files/94032686652.pdfIn PDF document text
    • http://cpviettin.com/upload/files/50193678481.pdfIn PDF document text
    • https://isosklo.cz/uploads/xasopinumiwekesegij.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/fzgW7-mxBc0/uplcv?utm_term=find+me+andre+aciman+read+onlinePDF 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_off0000de82.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDE82 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f694.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF694 17716 bytes
SHA-256: d65bc274f29a921386c8f3f8aa2864d3d538cf718de1bddbcd908115d701b43e
font_02_sfnt_off00012448.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12448 10240 bytes
SHA-256: b391387744389996e3d340adfe393b8b9c1d4ed6d0251aeeca5574a0f4822c08