Malicious PDF — malware analysis report

Static analysis result for SHA-256 913c51a8f61a4143…

MALICIOUS

PDF

93.8 KB Created: 2021-06-25 23:47:50 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 92a1bf3c6601331f0efe07271f8d59e0 SHA-1: 0ac98a9d6fea25b53bf1da7c3ad4374f3e5a92dc SHA-256: 913c51a8f61a414363b9ccee37c7de1fdc7f15e932dbcb5f173efb422bc316b5
96 Risk Score

Malware Insights

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

The PDF contains a link farm pointing to numerous URLs, many of which are hosted on compromised WordPress sites. The ML classifier strongly indicated maliciousness, and the presence of multiple links on disposable hosting suggests an attempt to distribute malicious content or redirect users to phishing sites. No scripts were extracted, but the structure itself is indicative of a malicious lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9989

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://www.aserspa.net/wp-content/plugins/super-forms/uploads/php/files/gsvimtar7hjj5v5tsctp2419bh/ruwofagomeve.pdf
    • https://smithsgame.com/calisma2/files/uploads/kelilonudefinalavaz.pdf
    • https://www.asahinafunnels.com/wp-content/plugins/super-forms/uploads/php/files/ru8smvmqh6q499dtdqbp8sfep8/xagowalinoliseji.pdf
    • https://artsketch.ru/wp-content/plugins/super-forms/uploads/php/files/43d7201ba803d97565b8f2be6a604dee/vetudizamukasaminalunelob.pdf
    • http://claudiodauelsberg.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16080e33aa81aa---14779603795.pdf
    • http://constructionone.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160702388edd58---70758310705.pdf
    • http://cohn-vossen.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608e5d835508f---rofivug.pdf
    • http://optimus.org.au/wp-content/plugins/formcraft/file-upload/server/content/files/160a32b3cc7aec---tepisazit.pdf
    • http://www.esthemed.ch/wp-content/plugins/formcraft/file-upload/server/content/files/160bced936061b---pugir.pdf
    • http://dabaizhongxue.com/upload_fck/file/2021-5-22/20210522130723611142.pdf
    • https://alismobile.co.uk/wp-content/plugins/super-forms/uploads/php/files/ede6dfa193799972cd115ecfd99053e6/30175266293.pdf
    • http://aeronautike.com/userfiles/file/lotamex.pdf
    • https://www.chartsunlimited.com.ph/wp-content/plugins/formcraft/file-upload/server/content/files/160d41772334f3---35527977490.pdf
    • http://mas.vacations/wp-content/plugins/formcraft/file-upload/server/content/files/160bdaf8ba6d94---36807218559.pdf
    • http://cpils.com/userfiles/file/63607051960.pdf
    • https://www.taxikladis.gr/wp-content/plugins/formcraft/file-upload/server/content/files/160772d5cbc9c8---toliz.pdf
    • http://igabana.com/upfolder/e/files/20210605002939.pdf
    • http://www.naturapreserved.com/wp-content/plugins/formcraft/file-upload/server/content/files/16072356ebd4dd---565894753.pdf
    • https://avenirpourtous.fr/wp-content/plugins/formcraft/file-upload/server/content/files/160927aee72a44---niririrogesunez.pdf
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/16081212c2ec63---30516160337.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/PmAiG5ZyT-k/uplcv?utm_term=frick+collection+library
    • 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_off00010994.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x10994 16792 bytes
font_01_sfnt_off000121a6.bin
0fb63863d2e292f97e255b2398b536abdf4f88fe35e314efca4a536e8fc8021a
pdf-font-stream PDF embedded font (sfnt) at offset 0x121A6 18524 bytes
font_02_sfnt_off0001510f.bin
69d1f3cc963a7ee818e8ff2b3caf225e00ad3fc87f9d5bd73116c511dfd13b1a
pdf-font-stream PDF embedded font (sfnt) at offset 0x1510F 10376 bytes