Malicious PDF — malware analysis report

Static analysis result for SHA-256 87d24eca53dded69…

MALICIOUS

PDF

89.3 KB Created: 2021-09-03 07:18:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: 25bf106cb69255b2cdd7e42f8f230ee4 SHA-1: 36a0ffa3e146a9622e22107343ddc0a69127d643 SHA-256: 87d24eca53dded690208ac12bfa4c33a17a35b0068cc56b85a0d88dc747b0de6
164 Risk Score

Malware Insights

MITRE ATT&CK
T1059.007 JavaScript T1566.001 Spearphishing Attachment

The sample is identified as malicious by ClamAV and a machine learning classifier, with heuristics indicating the presence of JavaScript actions and links to compromised WordPress upload storage and other disposable hosting. The JavaScript likely facilitates redirection to these compromised sites, which are often used for phishing or to host further malicious content. The PDF structure and link farms suggest an attempt to obscure the final destination and evade detection.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9942

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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.
  • JavaScript action low PDF_JAVASCRIPT
    PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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 http://music-saikung.com/ckfinder/userfiles/files/71286706851.pdf In PDF document text
    • http://parcroyale.hk/userfiles/51285524068.pdfIn PDF document text
    • http://proxima-design.cz/files/file/13053182610.pdfIn PDF document text
    • https://oxfordjsr.com/userfiles/file/70806366335.pdfIn PDF document text
    • http://www.photobreak.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1607cd2fa5ebbe---wedekifowuve.pdfIn PDF document text
    • http://ms-krmelin.cz/app/webroot/files/files/64256547853.pdfIn PDF document text
    • http://careerhack.net/wp-content/plugins/formcraft/file-upload/server/content/files/160af6401b719b---7396043528.pdfIn PDF document text
    • https://florerialafloresta.com/ckfinder/userfiles/files/75281492297.pdfIn PDF document text
    • http://manufim.co.il/wp-content/plugins/formcraft/file-upload/server/content/files/160a14d87e9427---13135410266.pdfIn PDF document text
    • http://bloomx.com/sites/all/sites/bloomx.com/files/konekod.pdfIn PDF document text
    • http://creativeindustries.ru/uploads/userfiles/file/572845339.pdfIn PDF document text
    • http://ekogamma.pl/javascript/ckfinder/userfiles/files/18815019890.pdfIn PDF document text
    • https://sportli.co.il/wp-content/plugins/formcraft/file-upload/server/content/files/160b61b7c7ecc7---lebokutifadeliwawedi.pdfIn PDF document text
    • https://mamproducciones.es/wp-content/plugins/formcraft/file-upload/server/content/files/160a972f128504---nazigerakaraxexabotu.pdfIn PDF document text
    • http://patriabrno.cz/userfiles/files/xajasiset.pdfIn PDF document text
    • http://krzysztofmalec.pl/gfx/fck/file/jaxefapomukirotani.pdfIn PDF document text
    • https://cplastik.cz/data/cms/file/sozerifalofenoda.pdfIn PDF document text
    • https://lightupalife.org.uk/wp-content/plugins/formcraft/file-upload/server/content/files/161315ca71d242---pilekuboz.pdfIn PDF document text
    • http://www.optionassurance.ca/wp-content/plugins/formcraft/file-upload/server/content/files/1607d0ccf8c0de---purako.pdfIn PDF document text
    • https://aquaticlandscape.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a096cc5ce42---9834053471.pdfIn PDF document text
    • https://ilc.ua/wp-content/plugins/super-forms/uploads/php/files/088df5ib9gicb52vgjqd1554t0/rifefero.pdfIn PDF document text
    • https://eobliecky.sk/userfiles/file/52862972678.pdfIn PDF document text
    • http://sipsak.nl/userfiles/file/wuzozepe.pdfIn PDF document text
    • http://www.finanzanlagen-honorarberatung.de/wp-content/plugins/formcraft/file-upload/server/content/files/16084f07878899---94023308772.pdfIn PDF document text
    • http://www.driftime.ee/wp-content/plugins/formcraft/file-upload/server/content/files/160da1d2be0c92---makex.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/FevRqgeaUVY/uplcv?utm_term=presidian+phone+manualPDF 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_off0000f5e0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF5E0 19008 bytes
SHA-256: fe64e15d862a71b2b10d31653da7961780b0131dbf8123b0a2121b054fd95ca9
font_01_sfnt_off00012771.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12771 10660 bytes
SHA-256: 4f46a77fbaf42a159e8a2795b93d8e0ae8c1a7128ce05acc0281759e1b95a067
font_02_sfnt_off00013f92.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13F92 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1