Malicious PDF — malware analysis report

Static analysis result for SHA-256 9ef779085fbe2996…

MALICIOUS

PDF

69.9 KB Created: 2021-09-24 21:02:10 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 8077858fd1d07012fdb7db77ee9f9e65 SHA-1: 3fe88fd7e650e41e94f47dbe626fe69bd566129d SHA-256: 9ef779085fbe2996fe138dcf5d1bcd2e6829ff52424a088949388abbdd0b7801
96 Risk Score

Malware Insights

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

The PDF contains a link farm with numerous URLs pointing to compromised WordPress sites, identified by heuristics like 'PDF_SEO_DISPOSABLE_LINK_FARM' and 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM'. The ML classifier also strongly indicated maliciousness. While no scripts were extracted, the structure suggests the document is designed to redirect users to potentially malicious content or phishing pages.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

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://maydongy.com/wp-content/plugins/super-forms/uploads/php/files/1027djk6b0u483drilf7lp9omv/2726163113.pdf
    • https://anaksemut.com/contents/files/kosava.pdf
    • http://danies.ru/ckfinder/userfiles/files/9014109551.pdf
    • https://stdtekstil.com/upload/ckfinder/files/nivonukukenef.pdf
    • https://betsin.org/userfiles/files/43180015747.pdf
    • https://seroinstitute.com/wp-content/plugins/super-forms/uploads/php/files/42636755e5441f4f292515fd7dcce93c/90081931679.pdf
    • http://tv-kitchen.ru/files/files/47581386362.pdf
    • https://parlagame.com/calisma2/files/uploads/59822744417.pdf
    • http://chingyi.tw/userfiles/files/66439912045.pdf
    • http://cbstav.cz/file/46920612899.pdf
    • http://www.cuadernos.in/wp-content/plugins/formcraft/file-upload/server/content/files/16143a7898bd6d---95771940839.pdf
    • http://chipublichouse.com/ckfinder/userfiles/files/pokenujupasulal.pdf
    • http://carsonpokebar.com/uploads/files/fomejezasi.pdf
    • https://santa.sg/images/users/00000000/files/kugeligarofelamusema.pdf
    • http://customize.fr/fckeditor/editor/filemanager/connectors/php/img/Editor/file/68444473946.pdf
    • http://sjzhtchem.com/upload/files/15927075319.pdf
    • http://rebornfair.com/FileData/ckfinder/files/20210917_E62169EF6C16BD56.pdf
    • http://urs-certification.com/gais/image/file/leziwafulikira.pdf
    • http://patronusalapitvany.hu/public_html/upload/selixisexases.pdf
    • http://bpsstudio.hu/uploads/36280111915.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/BvfzZFkJO3s/uplcv?utm_term=what+is+physical+keyboard+in+android
    • 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_off0000aece.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1		 pdf-font-stream PDF embedded font (sfnt) at offset 0xAECE 16792 bytes
font_01_sfnt_off0000c6e5.bin
c620bdfdb66ab14d504dcb7c87d51634c2fb1796119e38d30ea16f9b37d2c1a9		 pdf-font-stream PDF embedded font (sfnt) at offset 0xC6E5 10948 bytes
font_02_sfnt_off0000e00d.bin
60fdef77f4200640e2acd4e1c5caad1689829e7c8bdc228dbe92c23cec2103c0		 pdf-font-stream PDF embedded font (sfnt) at offset 0xE00D 16420 bytes

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