Malicious PDF — malware analysis report

Static analysis result for SHA-256 cd8f77fc1dc5a50e…

MALICIOUS

PDF

95.8 KB Created: 2021-09-23 06:49:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 1e94db5a4102561fd7d5633836a437e1 SHA-1: a1a068651bfc534c00db9c0247f5f806d005e8c4 SHA-256: cd8f77fc1dc5a50e69c7140d527c82b1265547b64c38d1cc9fb0e490b383572b
136 Risk Score

Malware Insights

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

The PDF contains multiple heuristics indicating malicious intent, including a link farm pointing to compromised CMS uploads and disposable hosting, and a high-confidence ML classifier flagging it as malicious. The 'SE_BROWSER_INSTALL_LURE' heuristic strongly suggests the document's purpose is to trick the user into installing malicious browser extensions or updates. While no scripts were directly extracted, the nature of the lures and the embedded URLs suggest a potential for further malicious activity, possibly involving JavaScript execution or exploitation.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9965

Heuristics 6

  • Browser extension / update installation lure high SE_BROWSER_INSTALL_LURE
    Document tells the user to install a browser extension, plugin, viewer, or browser update to view content — a common social-engineering path for credential theft and malware installation
  • 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://unseretochter.ch/images/file/37864209951.pdf In PDF document text
    • http://dailyliving.nl/ckfinder/userfiles/files/1524951670.pdfIn PDF document text
    • http://tcsklife.com/filespath/files/20210913125133.pdfIn PDF document text
    • http://halmar.info/userfiles/file/16163716682.pdfIn PDF document text
    • http://coimbrasoftware.hu/images/uploads/files/28043830518.pdfIn PDF document text
    • http://cloudinfo01.smartevolve.com/images/ckeditor/files/fafoxodibokagaz.pdfIn PDF document text
    • http://boletin.alicantehosteleria.com/lib/ckfinder/userfiles/files/kunuvat.pdfIn PDF document text
    • https://baongochoa.com/upload/file/manoruferiwawow.pdfIn PDF document text
    • http://www.hebrewforreadingcomprehension.com/content/18113416023.pdfIn PDF document text
    • http://remont-m.com/userfiles/file/78554885253.pdfIn PDF document text
    • http://hyundaihungthinh.com/uploads/images/files/sunizul.pdfIn PDF document text
    • http://enkepharma.com/upload/files/95160563738.pdfIn PDF document text
    • https://giltmorestukko.hu/ckfinder/userfiles/files/81940788469.pdfIn PDF document text
    • https://cashcruis.ru/wp-content/plugins/super-forms/uploads/php/files/99e73fda59033d496a3b6d4028b70a68/97014253761.pdfIn PDF document text
    • https://adesso-moosburg.de/images/file/sovegesisatinux.pdfIn PDF document text
    • http://swaminarayangm.org/userfiles/file/40142736714.pdfIn PDF document text
    • https://megacook.pt/site/upload/file/zowebesitav.pdfIn PDF document text
    • http://ciaomamma.hu/editor_up/80669480343.pdfIn PDF document text
    • http://studiovalecchi.it/userfiles/files/36349010848.pdfIn PDF document text
    • http://nifaelectronics.com/userfiles/file/31637526453.pdfIn PDF document text
    • http://clairvoyantinfotech.com/demo/images/58026905578.pdfIn PDF document text
    • https://amagi.la/wp-content/plugins/formcraft/file-upload/server/content/files/1612fac4d6dc9a---xomatusapegetosunefir.pdfIn PDF document text
    • https://www.budgetskemaet.dk/wp-content/plugins/formcraft/file-upload/server/content/files/16134ae81b7343---74422676281.pdfIn PDF document text
    • https://888nv.ru/userfiles/file/56876223685.pdfIn PDF document text
    • http://leadingedgecorporate.com/user_images/file/84058577170.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/zMnd8XtcwSM/uplcv?utm_term=friends+1+season+1+episode+english+subtitlesPDF 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_off0001087e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1087E 21140 bytes
SHA-256: a1aaf005a93bfc648bf9f9ed83a94e62ab670bf3b0f11433ba7fadcc10323fd1
font_01_sfnt_off00013fe6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13FE6 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000157fd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x157FD 10940 bytes
SHA-256: 70fcde6553577902ca3866716d13044b51c263db50baf61ca0c2cd88b1fbf6ba

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