Malicious PDF — malware analysis report

Static analysis result for SHA-256 a3b3ad30355bbfc2…

MALICIOUS

PDF

72.6 KB Created: 2021-09-29 09:35:56 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 29f0a95de0ba9becc40c12b6c48f2d63 SHA-1: 43e42b165ce24d7a41b79c3603b123e0ffd3f7a5 SHA-256: a3b3ad30355bbfc20cf0689cdd7c858fe4fa742a303952937bb250a8fdf8909f
104 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains an embedded JavaScript stream and a link farm pointing to multiple compromised websites, suggesting an attempt to redirect users to malicious content. The ML classifier strongly indicates maliciousness, and the presence of external URIs and a link farm heuristic further supports this. The primary attack pattern involves luring users to download further malicious PDFs from compromised upload storage.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9971

Heuristics 6

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. 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 https://netwindowvn.com/uploads/userfiles/file/gupuvafozurimotebuko.pdf In PDF document text
    • http://sun-tes.ru/files/file/24991993045.pdfIn PDF document text
    • https://evocative.ru/wp-content/plugins/formcraft/file-upload/server/content/files/161368f2bb729f---rudaxetigerupotalutub.pdfIn PDF document text
    • http://kodemari.info/data/files/refife.pdfIn PDF document text
    • http://24hnbc.com/assets/ckfinder/core/connector/php/uploads/files/pisozefulavulagil.pdfIn PDF document text
    • http://deltools.com/userfiles/file/mapavi.pdfIn PDF document text
    • http://anchor-m.com/js/upload/files/sositefetufiboxan.pdfIn PDF document text
    • http://www.otevrenysklep.cz/ckfinder/userfiles/files/3087512216.pdfIn PDF document text
    • https://www.hdontheroadnapoli.it/wp-content/plugins/formcraft/file-upload/server/content/files/161336b6b22d8f---zevozadawuvudeta.pdfIn PDF document text
    • http://lmalaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/54459303006.pdfIn PDF document text
    • http://escolacaritas.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613c0bbabecb5---donamamexabavokoroju.pdfIn PDF document text
    • http://sns.hu/_user/file/gexanogowotubul.pdfIn PDF document text
    • http://ping-property.com/user_img/files/21853717538.pdfIn PDF document text
    • http://palaciodelosnavas.com/userfiles/file/68925518588.pdfIn PDF document text
    • https://kawanmto.info/contents/files/91485035483.pdfIn PDF document text
    • http://dmkert.hu/files/file/46213316092.pdfIn PDF document text
    • https://www.pepinieres-gey.fr/ckfinder/userfiles/files/69426178666.pdfIn PDF document text
    • https://hoangmailogistics.com/asset/site/files/zugaxitamasatokaf.pdfIn PDF document text
    • http://shahnawazonline.com/uploads/files/jujidotolexati.pdfIn PDF document text
    • https://ferdavagnar.is/images/fck/file/88313527793.pdfIn PDF document text
    • https://omprintandpack.com/userfiles/file/91782969177.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/Om9ozkHLxGw/uplcv?utm_term=juegos+android+online+con+amigosPDF 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_off0000b6a4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB6A4 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000ceb6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCEB6 17892 bytes
SHA-256: 882c8d6b8aed800b18d01ecb0c51ed95f1bec880d730fe35cad1561cae603e07
font_02_sfnt_off0000fcb8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFCB8 10708 bytes
SHA-256: 6157b174fd58caf90a20632d5d39f218895e539504b1ec62bb52fe389e6b56a5