Malicious PDF — malware analysis report

Static analysis result for SHA-256 8255574d603efd3c…

MALICIOUS

PDF

76.4 KB Created: 2021-09-07 01:20:56 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 8e5bf514036b5f589933165a078d445f SHA-1: 2a418352696274c25849b071aecc716a535a83fe SHA-256: 8255574d603efd3cd8f4fee12113377849909634dacd9cf3c5c245a0e9b855b8
96 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs pointing to compromised CMS uploads and disposable domains, indicating a link farm strategy. The ML classifier strongly flagged this PDF as malicious. While no scripts were extracted, the extensive use of external links suggests the document is designed to redirect users to potentially malicious sites, possibly for phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

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://coretry.ru/uplcv?utm_term=anemia+regenerativa+en+perros+pdf PDF link annotation
    • https://vico-domrep.com/ckfinder/userfiles/files/lojawede.pdfIn PDF document text
    • https://alfa-pechati.ru/wp-content/plugins/super-forms/uploads/php/files/ea30029f55aa28e267b5f3b426615ae3/natinopabilej.pdfIn PDF document text
    • https://graffitipaintstudio.com/wp-content/plugins/super-forms/uploads/php/files/34d7047b11ad5b6190eae1881e5d6e1a/38466506868.pdfIn PDF document text
    • http://geometramaurotozzi.it/userfiles/files/3985318898.pdfIn PDF document text
    • http://aunay-sous-auneau.fr/ckfinder/userfiles/files/36575951616.pdfIn PDF document text
    • http://cargo3030.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1606c9bf9f0343---35928968422.pdfIn PDF document text
    • http://www.greenbriarpropmgmt.com/wp-content/plugins/super-forms/uploads/php/files/64eee985a288c6c0b594a4f4628d40ef/fisuvotazixagazuxaje.pdfIn PDF document text
    • https://thehouseconcert.com/ckfinder/userfiles/files/xezurizuviwidukigunanosi.pdfIn PDF document text
    • http://accu-chek-event.com/ckupload/files/pakapenuputipunit.pdfIn PDF document text
    • https://senzedigicraft.com/wp-content/plugins/super-forms/uploads/php/files/04c334e27477cf79fad562952e39450e/dojaxa.pdfIn PDF document text
    • http://garmagostaran.com/Upload/file/68344014277.pdfIn PDF document text
    • https://aimara-bg.com/userfiles/file/gaxosukalowamiw.pdfIn PDF document text
    • http://omni-links.com/images/blog//file/72103336916.pdfIn PDF document text
    • http://alarcon-v.com/editor_upload_image/file/vikaduxenevin.pdfIn PDF document text
    • https://sitpchemcieszyn.pl/_sitpchem/file/5729245871.pdfIn PDF document text
    • http://uralinteh.com/uploads/files/xamijalojolifuxipabe.pdfIn PDF document text
    • http://marinapogon.pl/upload/file/xefalin.pdfIn PDF document text
    • https://stoneappeal.in/FCKeditor/file/56749869367.pdfIn PDF document text
    • http://opalbiosciences.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a5f03e91d36---newinipe.pdfIn PDF document text
    • http://blissworldbeauty.com/newerac2c/userfiles/file/27541661907.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_off0000c9ea.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC9EA 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000e1fc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE1FC 16244 bytes
SHA-256: 6490b5d8cfbab7febca51c154977efcf7197959fc28e48635eb8a580388863e2
font_02_sfnt_off00010b71.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10B71 10840 bytes
SHA-256: 61d7e459a125bb1150c78ceb3dce723ff72148c3b5fcc007b1db4d897e6248d6