Malicious PDF — malware analysis report

Static analysis result for SHA-256 81a6db2c7914a251…

MALICIOUS

PDF

78.4 KB Created: 2021-09-23 07:18:20 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: f9d6dfc28aabbd1947a6901bf1d51410 SHA-1: 2a46d1813969ccdacd4315f08a4a850a15865136 SHA-256: 81a6db2c7914a251a333bcebfc4f332902b87c961cfb45d82fdff171896553d3
156 Risk Score

Malware Insights

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

The PDF file contains numerous embedded URLs, many of which point to compromised websites or disposable domains, indicating a link farm designed to redirect users. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or malware delivery. No scripts were extracted, but the extensive use of external links and the nature of the hosting suggest a multi-stage attack.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9982

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://crysiq.ru/uplcv?utm_term=android+image+upload+to+server+from+camera+and+gallery PDF link annotation
    • https://profesa.net/userFilesfile/29274833321.pdfIn PDF document text
    • http://grani-tonkogo-mira.ru/wp-content/plugins/super-forms/uploads/php/files/d4bf5f163b9ad8e3e63119b281822ed5/10240473983.pdfIn PDF document text
    • http://cpk.by/ckfinder/userfiles/files/90240127021.pdfIn PDF document text
    • http://rm-centr.ru/uploads/file/77493991510.pdfIn PDF document text
    • https://www.baust.edu.bd/app/webroot/ckfinder/userfiles/files/49939887626.pdfIn PDF document text
    • http://vonschickenconcord.com/uploads/files/ginemuvajazepofilesokujuf.pdfIn PDF document text
    • https://muahohangnhat.com/app/webroot/uploads/files/45658832345.pdfIn PDF document text
    • http://advocaatindex.nl/images/uploads/povovanuguxu.pdfIn PDF document text
    • https://dhesient.com/media/84834749503.pdfIn PDF document text
    • http://kernenshepler.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/fesaxajulijuxa.pdfIn PDF document text
    • http://arniestribu.com/campannas/file/tuzarizinexetomuxomuti.pdfIn PDF document text
    • https://holyfamilyhospitals.com/ckfinder/userfiles/files/zaxumosaxiw.pdfIn PDF document text
    • http://cy2hand.com/userfiles/83985998338.pdfIn PDF document text
    • http://www.groupementpecheduloir.com/ckfinder/userfiles/files/11274845852.pdfIn PDF document text
    • http://alimentosldm.com/userfiles/file/10795967918.pdfIn PDF document text
    • https://mediabandit.com/wp-content/plugins/formcraft/file-upload/server/content/files/16144facb49df4---3983094873.pdfIn PDF document text
    • http://www.kidnuri.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613fd44e52852---78439869233.pdfIn PDF document text
    • http://www.thunderesp.com/ckfinder/ckfinder.htmlfiles/35054914666.pdfIn PDF document text
    • http://wohingltd.com/userfiles/losilowid.pdfIn PDF document text
    • https://www.sabiamente.es/wp-content/plugins/formcraft/file-upload/server/content/files/1613e682b70882---79600280817.pdfIn PDF document text
    • http://www.plain-pied.com/editeur/ckfinder/userfiles/files/89421104655.pdfIn PDF document text
    • https://leosservices.com/userfiles/file/72523596074.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_off0000cce9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCCE9 11224 bytes
SHA-256: c0af29ad6e8d73b7e8fa7c1f5006e6e502e35da66d09a1a260da4e43b82202d4
font_01_sfnt_off0000e70e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE70E 17280 bytes
SHA-256: 555fcc87c1a6c2add3f35bb55051610b5f52688115691b0191dcbb4be9695d40
font_02_sfnt_off00011343.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11343 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1