Malicious PDF — malware analysis report

Static analysis result for SHA-256 838a4bbdbcda7d0b…

MALICIOUS

PDF

86.4 KB Created: 2021-07-01 13:29:58 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: fd1de6db3fa987a7bad9ae2f2a6ac767 SHA-1: a1ae01a3ed570327d489206693a12513cef5ed52 SHA-256: 838a4bbdbcda7d0b2484c11f98e519cb92f5f4e61f6dbcc8ff32b15c2db6e50c
156 Risk Score

Malware Insights

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

The PDF file was flagged by multiple heuristics and an ML classifier as malicious, with ClamAV identifying it as a phishing trojan. It contains numerous links to compromised WordPress upload storage, suggesting it is designed to host and distribute malicious content. The primary attack vector is likely exploitation of a PDF vulnerability to download a secondary payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9964

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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 http://www.kidnuri.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609af1de6952a---97978541725.pdf
    • https://husvagnsexpo.se/wp-content/plugins/formcraft/file-upload/server/content/files/1606ccaa664441---8674863005.pdf
    • https://imagebuzz.net/ckfinder/userfiles/files/xeguvugixijo.pdf
    • https://mziagroup.com/wp-content/plugins/super-forms/uploads/php/files/hti9nv65u2kg6lfjc0ikqq3jfl/nosikatunaba.pdf
    • https://diversified-nj.com/wp-content/plugins/super-forms/uploads/php/files/b8138085e2e72106b2b1f6285c436dab/tosase.pdf
    • http://gayaarchi.com/userfiles/file/20210623214812.pdf
    • https://ludifrance.fr/userfiles/file/zipima.pdf
    • http://www.ausafrica.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/16094df7ad5e14---4778742551.pdf
    • http://la-roofers.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1607386a8f35d7---kijuduvetix.pdf
    • https://emergent-partners.com/wp-content/plugins/formcraft/file-upload/server/content/files/160757f30e7394---bikedi.pdf
    • https://dsodrecital.com/wp-content/plugins/formcraft/file-upload/server/content/files/16079e06c1246c---mosuxitajefupidalus.pdf
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/160795aaa54874---66027375354.pdf
    • http://trenermichal.pl/wp-content/plugins/formcraft/file-upload/server/content/files/1608096884d0ec---14042649215.pdf
    • https://boldvision.tv/wp-content/plugins/formcraft/file-upload/server/content/files/1609c5c014e679---ledegunavovafikane.pdf
    • http://penoplex24.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1608e539ac3703---21403032963.pdf
    • https://tehnol.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1609504f51a5ee---menitotiweluvewunon.pdf
    • http://aberdeeneyes.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16090888e36e0a---97411052055.pdf
    • https://www.andeanskyline.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606d40a8e935d---17428602872.pdf
    • https://tamtam.com.ua/wp-content/plugins/super-forms/uploads/php/files/f43e8d629e9f595ec949fa25b6d23f36/33422171136.pdf
    • http://alexanderkanevskyartgallery.com/clientMedia/file/tufogojopufozulije.pdf
    • https://primax.fr/wp-content/plugins/super-forms/uploads/php/files/10rvr7epoa4sose7u3fdvpcap4/tadifo.pdf
    • http://roycraft.ca/userfiles/file/sefalizadeje.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/Om9ozkHLxGw/uplcv?utm_term=the+vein+that+carries+oxygenated+blood
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ef7e.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xEF7E 16792 bytes
font_01_sfnt_off00010795.bin
97222e9b18a19a3311cdc7aa77cde4b91b934efcf66df684c13874d5f4050a52
pdf-font-stream PDF embedded font (sfnt) at offset 0x10795 11036 bytes
font_02_sfnt_off0001210e.bin
913a0a0aa0f268cf412586f504237fb143e7d2003facdc94b12f714dccb9f6a2
pdf-font-stream PDF embedded font (sfnt) at offset 0x1210E 16832 bytes