Malicious PDF — malware analysis report

Static analysis result for SHA-256 87d399b82fc6d452…

MALICIOUS

PDF

72.4 KB Created: 2021-06-25 14:43:49 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 1602ae18dafe198f0f3b5391091cbb60 SHA-1: dfaade5a6b65d3ee1c8f639bb582db835a23d2ac SHA-256: 87d399b82fc6d4529fb3198c77702cf2cee876511625e7dcf3df4237cb8cc154
96 Risk Score

Malware Insights

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

The ML classifier strongly indicated maliciousness, and several heuristics identified the PDF as a link farm pointing to compromised WordPress upload directories. The document body was heavily obfuscated and unreadable, suggesting an attempt to hide its true purpose. The presence of numerous links to potentially compromised sites indicates a phishing or redirection scheme.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9994

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 http://for-rent-antwerp.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a625b3c0850---82483595950.pdf
    • http://przedszkolenisko.pl/userfiles/file/jadijef.pdf
    • https://jordanadams.com/ckfinder/userfiles/files/32937210519.pdf
    • http://foire-fromages-et-vins.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a41df081cfe---69161869912.pdf
    • https://www.adilaltinsoy.com/wp-content/plugins/formcraft/file-upload/server/content/files/16072e1b203d29---78620048137.pdf
    • http://yaqeen-eg.com/userfiles/file/24361491004.pdf
    • http://odpadykj.cz/UserFiles/File/30715521332.pdf
    • http://asesorialuishervas.com/wp-content/plugins/formcraft/file-upload/server/content/files/16075dc6d1025b---21234945937.pdf
    • https://www.accidentinjuryalbuquerque.com/wp-content/plugins/super-forms/uploads/php/files/a7pct99naef56hudfhhprv8r70/xovikedu.pdf
    • https://www.certificagreen.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ce244127b66---77571813132.pdf
    • http://royalwedding.jp/images/blog//file/tirazizomotutateni.pdf
    • https://www.tifdip.com/wp-content/plugins/formcraft/file-upload/server/content/files/16083bcb3c851a---87885923057.pdf
    • http://bet-balance.com/userfiles/file/46480942642.pdf
    • http://vilaportugal.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608544321e400---73389994938.pdf
    • http://jtour.vn/userfiles/file/lixelusijexu.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/YTWXjIUwRh0/uplcv?utm_term=types+of+busses+in+computer
    • 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_off0000ba68.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1		 pdf-font-stream PDF embedded font (sfnt) at offset 0xBA68 16792 bytes
font_01_sfnt_off0000d27f.bin
e083a2d95841000b1d913d2fd5ded257bc925f3ed9b68caa21ab26cf15da84a3		 pdf-font-stream PDF embedded font (sfnt) at offset 0xD27F 10748 bytes
font_02_sfnt_off0000eb09.bin
f7a8ddfabb6e4c82b9c7f39d5c9deb3da557b5b694cc8a85ae4b37658f985b2e		 pdf-font-stream PDF embedded font (sfnt) at offset 0xEB09 16244 bytes

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