Malicious PDF — malware analysis report

Static analysis result for SHA-256 b8895d30ef4ba87c…

MALICIOUS

PDF

89.3 KB Created: 2021-08-22 16:46:41 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 980b45679fcffb9da58be0bbe49fc641 SHA-1: 37ecb745c152cf66ef067820cb079556a93a9ea2 SHA-256: b8895d30ef4ba87ca4e2e24922127ca80374664bb811dad882c6ea4aa871b9ca
96 Risk Score

Malware Insights

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

The PDF file contains a large number of embedded URLs, many of which point to PDF files hosted on various domains. Several heuristics indicate this is a link farm, with some links pointing to compromised CMS uploads. The ML classifier strongly flagged this PDF as malicious. While no scripts were extracted, the structure and URL distribution suggest a malicious intent, likely to distribute further malicious content or for SEO spam.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

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://stmarys-perthamboy.com/upload/File/97205607295.pdf In PDF document text
    • https://rumputhijau.com/contents//files/mutiruxunipokob.pdfIn PDF document text
    • http://prefinancovaniehypoteky.sk/res/file/99489036607.pdfIn PDF document text
    • https://balbok.net/admin/ckfinder/userfiles/files/57545356556.pdfIn PDF document text
    • https://besi.co/ckfinder/userfiles/files/medilexo.pdfIn PDF document text
    • http://alsumiri.net/wp-content/plugins/super-forms/uploads/php/files/986f27842b7aa96b8928fbc42e5501c5/71083802584.pdfIn PDF document text
    • http://phelieuviethung.vn/upload/files/55229752779.pdfIn PDF document text
    • https://www.southdownscellars.co.uk/ckfinder/userfiles/files/44584283366.pdfIn PDF document text
    • http://salonlomi.pl/wp-content/plugins/formcraft/file-upload/server/content/files/160d44ebb64422---puxaf.pdfIn PDF document text
    • http://akvari-um.ru/userfiles/file/jiwilodo.pdfIn PDF document text
    • https://primax.fr/wp-content/plugins/super-forms/uploads/php/files/rhd9i2tk0umpq8u9t6j2mdvaj1/10711655352.pdfIn PDF document text
    • http://polloricowings.com/uploads/files/87584297725.pdfIn PDF document text
    • https://www.litesourcenc.com/wp-content/plugins/super-forms/uploads/php/files/0c6ac9b8217180d7cbf7c28426034c20/57133652654.pdfIn PDF document text
    • http://www.sunarsurdurulebilir.com/wp-content/plugins/super-forms/uploads/php/files/jebveqirfh9pl3c03grg29km54/97078873312.pdfIn PDF document text
    • http://www.nationaalgolfcongres.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160a26b019da4b---tusob.pdfIn PDF document text
    • https://lesura.net/userfiles/file/53064182457.pdfIn PDF document text
    • https://takeorders.online/wp-content/plugins/super-forms/uploads/php/files/hebbevj22eo7psnr84jodqr6ir/51846737188.pdfIn PDF document text
    • https://alquimia.in/admin/fckeditor/editorfile/16819440820.pdfIn PDF document text
    • https://www.grandiosa.is/wp-content/plugins/super-forms/uploads/php/files/o7uujukinheomld5g6vldci9i0/48905146759.pdfIn PDF document text
    • https://cashmeredreams.com/wp-content/plugins/super-forms/uploads/php/files/0653bf3c972ba2e63cc8e88e4f682c0c/zopus.pdfIn PDF document text
    • http://vinhhangvien.com/upload/files/vupedobolerotikev.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/BvfzZFkJO3s/uplcv?utm_term=which+insurance+is+best+for+dentalPDF 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_off0000f9ec.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF9EC 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off000111fe.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x111FE 16972 bytes
SHA-256: 13965283bb6a0cbb7aff0f4d192b7a3ff3343d2fd16a6b969864f4849d4313c6
font_02_sfnt_off00013e56.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13E56 10808 bytes
SHA-256: abc9510ea6137b599eac2e531e183fd81e31c70480db9631401cce6811a46083