Malicious PDF — malware analysis report

Static analysis result for SHA-256 cd35856d998383b7…

MALICIOUS

PDF

77.0 KB Created: 2021-09-07 21:29:37 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: f921e4de58d9668ef6c106274e9017b3 SHA-1: 7b9e3ea20ade11295409eb2823f4594e1d1e14ba SHA-256: cd35856d998383b7a6bc6aaa0227c8d0058c5b012dc1c03527e174c595b80d1c
136 Risk Score

Malware Insights

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

The PDF document contains numerous links to external sites, many hosted on compromised WordPress installations, suggesting a link farm or phishing lure. The 'SE_REMOTE_SUPPORT_LURE' heuristic indicates the document likely instructs the user to install or connect to a remote support tool, which is a common tactic for gaining unauthorized access. While no scripts were explicitly extracted, the presence of embedded URLs and the ML classifier's high confidence score point towards malicious intent, likely to facilitate further compromise or data theft.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9953

Heuristics 6

  • Remote-support tool lure high SE_REMOTE_SUPPORT_LURE
    Document instructs the user to install, open, or connect with a remote-support tool such as AnyDesk, TeamViewer, Quick Assist, or ScreenConnect — high-risk in an unsolicited document
  • 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://pistant.ru/uplcv?utm_term=gui%C3%B3n+t%C3%A9cnico+pdf PDF link annotation
    • http://3suntech.com/UploadFile/file/20210813162913660.pdfIn PDF document text
    • http://wpklaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/medemogebivome.pdfIn PDF document text
    • http://viaterrestre.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160a08e04d64fe---julabijofazefalofopurinut.pdfIn PDF document text
    • https://www.webhisto.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/1607e570b7a464---91590385362.pdfIn PDF document text
    • https://velvetskin.pl/wp-content/plugins/super-forms/uploads/php/files/a8beb64caa1181fb862dee76263d8333/25521161853.pdfIn PDF document text
    • http://villa-carlshorst.de/sites/default/files/file/56029635239.pdfIn PDF document text
    • https://www.baileysmilk.com/wp-content/plugins/super-forms/uploads/php/files/4306eb97b6964a1f3affcca428976721/rofetudifaki.pdfIn PDF document text
    • https://www.kalirich.com/wp-content/plugins/super-forms/uploads/php/files/atdndaj8beniu4i1onndih75u7/81231774483.pdfIn PDF document text
    • https://baigiangtoanhoc.com/upload/files/lokawufirijuxikini.pdfIn PDF document text
    • https://shining4u.com/wp-content/plugins/super-forms/uploads/php/files/8bb068ca0cd59cac94fe35476afb9a00/vubizozekenafemitub.pdfIn PDF document text
    • https://drahmetbostanci.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a94410051be---natenivigonojixamibowonig.pdfIn PDF document text
    • https://lcd96.ru/wp-content/plugins/super-forms/uploads/php/files/d3bf5214d36b0a797befb9b754d7f929/10924890697.pdfIn PDF document text
    • https://serviceservice.eu/userfiles/file/25911145583.pdfIn PDF document text
    • http://sartor.ru/upload/files/sanufibote.pdfIn PDF document text
    • https://mudateconmigo.cl/wp-content/plugins/super-forms/uploads/php/files/bcc00a35932a14cff5dce624d542c674/47831579881.pdfIn PDF document text
    • http://zadonskiy.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1606cad7c1755e---92115785063.pdfIn PDF document text
    • https://vuaship.com/wp-content/plugins/super-forms/uploads/php/files/cau36eiti84p1krb6ktkj4d7gm/bovovabipujitaxe.pdfIn PDF document text
    • https://vallejardin.com/wp-content/plugins/super-forms/uploads/php/files/c7a5dd560c6ecf9a1dd565be66f11683/2461240656.pdfIn PDF document text
    • https://www.simplythebestevents.ca/wp-content/plugins/formcraft/file-upload/server/content/files/160c64d7cb5ecd---95059834874.pdfIn PDF document text
    • https://www.masismarketing.com/wp-content/plugins/super-forms/uploads/php/files/42ed5d93677ba77ce977c40a160ae2b4/tetovamidit.pdfIn PDF document text
    • http://agisinfo.ru/uploads/content/files/kofemaviseleximolina.pdfIn PDF document text
    • http://nfc.soo.jp/file/fogamelerejodowutoxuvok.pdfIn PDF document text
    • https://bibliotheque-des-arts.ch/ckfinder/userfiles/files/48587159430.pdfIn PDF document text
    • 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_off0000c844.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC844 10436 bytes
SHA-256: 330cbd28081d859b39962ae09fc37c7432495f6e499f1b37034cc2387ed88151
font_01_sfnt_off0000dfc3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDFC3 18108 bytes
SHA-256: fdc6e5b916758253115f31ce2c66eedb7e19f8327d66ffc55bd397e64a47b180
font_02_sfnt_off00010d09.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10D09 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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