Malicious PDF — malware analysis report

Static analysis result for SHA-256 c9bb6ccb3d8a5442…

MALICIOUS

PDF

78.6 KB Created: 2021-09-05 14:23:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 81c81012171a52d493c9801b182d9edc SHA-1: 185b239a4333df9dea0394ec08d7aca66b01ced0 SHA-256: c9bb6ccb3d8a544252f17aae4d95fee70ebf901daefefe2798033db522a5eea3
96 Risk Score

Malware Insights

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

The PDF file contains a link farm, with numerous URLs pointing to various domains, some of which are hosted on compromised CMS uploads. The ML classifier strongly indicates maliciousness, and the structure suggests an attempt to lure users to external sites. No scripts were extracted, but the overall pattern points to a malicious document likely delivered via spearphishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9958

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 http://barudan.hk/UploadFile/file/20210810143626448.pdf In PDF document text
    • https://www.bussmann-tiefbau.de/ckfinder/userfiles/files/jexajob.pdfIn PDF document text
    • http://zhongguohuachun.com/d/files/susutijezuvabuniniba.pdfIn PDF document text
    • http://kinel-hunter.ru/upfiles/file/13097349324.pdfIn PDF document text
    • http://roland-toys.eu/userfiles/file/89688282602.pdfIn PDF document text
    • http://coss-wynn-reunion.com/clients/d/db/dbe3622004495b304d8703879a486b7d/File/6177605121.pdfIn PDF document text
    • http://mijneigenlift.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160adc9e74edbb---wubaxalowodifalatuxis.pdfIn PDF document text
    • http://pizzeriadevita.it/userfiles/files/wikegukubojomomige.pdfIn PDF document text
    • https://ocvirapuato.com.mx/wp-content/plugins/super-forms/uploads/php/files/cdf38e94d7db842f1d8f40f34c18b77c/44907808894.pdfIn PDF document text
    • https://marigabung.com/contents//files/xiruzegaxe.pdfIn PDF document text
    • http://www.deewanalarab.com/up_imgs/84986837898.pdfIn PDF document text
    • https://aarhuskortet.dk/images/file/lefusesunoga.pdfIn PDF document text
    • https://trimix.bg/UserFiles/File/38686178725.pdfIn PDF document text
    • http://petraifevronii.ru/ckfinder/userfiles/files/32331357232.pdfIn PDF document text
    • http://recamonde.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1609166b344477---4253085043.pdfIn PDF document text
    • http://aksaaydinlatma.com/img/editor/image/file/46914365557.pdfIn PDF document text
    • http://romanakladatelstvi.cz/userfiles/file/modutobofekiwinuvibovuvi.pdfIn PDF document text
    • https://homeuu.biz/upload/ckeditor/pages//files/fadeligumiwevobidejogid.pdfIn PDF document text
    • http://asupuro.com/user_data/image//file/detogexomalewakipimu.pdfIn PDF document text
    • http://rfaaa.com/UploadFile/file/20210807180521755.pdfIn PDF document text
    • https://www.denisonlandscaping.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608fc9f33896a---11250024425.pdfIn PDF document text
    • https://lmcmanager.com/ckfinder/userfiles/files/fuvavulepojizijotexuwi.pdfIn PDF document text
    • http://skuplaptop.pl/wp-content/plugins/formcraft/file-upload/server/content/files/1608a7cf5e2e06---segokiwikejoxulurogeki.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/fzgW7-mxBc0/uplcv?utm_term=add+integers+worksheet+pdfPDF 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_off0000d04b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD04B 10728 bytes
SHA-256: 5a23c48d1a103ea7e0f4df50b940591e8ceddbef81f4ac3d44152035c3b8c2f5
font_01_sfnt_off0000e8b9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE8B9 17016 bytes
SHA-256: a8870057e8951f6fea667cc5138e851d6db6437f44559dbdccf939eb0bd1a625
font_02_sfnt_off0001151f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1151F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1