Malicious PDF — malware analysis report

Static analysis result for SHA-256 e677278d4d14772a…

MALICIOUS

PDF

70.6 KB Created: 2021-10-01 00:06:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 4f89796e5a454e30720b8ac84e75a63f SHA-1: 8d526240c6326c28a56768fa7773d984ccf9c751 SHA-256: e677278d4d14772aa7a221cc5bab2dd70e4ea767322c2bd1459d477d407fd452
156 Risk Score

Malware Insights

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

The file was identified as malicious by ML classifiers and ClamAV, specifically as a phishing trojan. Static analysis revealed it functions as a link farm, containing numerous URLs pointing to external resources, many hosted on compromised CMS upload directories or disposable domains. The PDF document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather as a container for malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

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://zhuoer.ltd/userfiles/file/86659062655.pdf
    • https://mindweave.co.uk/wp-content/plugins/super-forms/uploads/php/files/lnpa3l3a1iqplf4uva8kaf94of/dididozedekijato.pdf
    • https://dcimx.com/files/40447959002.pdf
    • http://tupnate.com/ckfinder/userfiles/files/dararumefubemogomuvusa.pdf
    • http://geodavidepini.it/userfiles/files/19370982520.pdf
    • https://tahitotfalu.hu/ckfinder/userfiles/files/84863023200.pdf
    • http://mn-print.ru/ckfinder/userfiles/files/lasaziz.pdf
    • http://mail.me.ntou.edu.tw/ckfinder/userfiles/files/20210914_012506.pdf
    • https://m-astar.com/UserFiles/files/kopadepizabutesokab.pdf
    • https://baobiachau.com/luutru/files/zoniwozun.pdf
    • https://www.frontierexim.com/wp-content/plugins/super-forms/uploads/php/files/uspcmt102hdb842k6kcdg8u347/peguzorebid.pdf
    • http://circuitvietnamcambodge.com/hinhanh/file/kejetarodorutukabepulep.pdf
    • http://es-umzuege-transporte.de/wp-content/plugins/super-forms/uploads/php/files/7f5af7409aeaea76c564f82cf7527265/lufotemapi.pdf
    • http://www.absolutecateringla.com/wp-content/plugins/formcraft/file-upload/server/content/files/16151288db97fb---37953729323.pdf
    • http://laskod.hu/userfiles/file/44065143513.pdf
    • http://halongbaycruises.org/upload/files/xenufovotefojuxesumorum.pdf
    • http://triumphtoday.org/wp-content/plugins/formcraft/file-upload/server/content/files/161342b11a045f---josurazifa.pdf
    • http://unitec-egypt.net/userfiles/file/nenep.pdf
    • http://evabody.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1613c9e773e3f6---mokidojunijexexuz.pdf
    • http://kbo.pl/ckfinder/userfiles/files/nezurofewuraguzupopirev.pdf
    • http://iranjobex.com/cache/fck_files/file/97747320954.pdf
    • https://listocrm.com/userfiles/files/15258999502.pdf
    • http://ecompletecontact.com/ckfinder/userfiles/files/39962696552.pdf
    • http://dobermanncz.eu/files/sajagivino.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BvfzZFkJO3s/uplcv?utm_term=all+phone+pattern+combinations
    • 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_off0000b1d8.bin
d9512bdadda4155696479560ead6ae03c2c41c3502e6ba43ae06a8473d3b5db3
pdf-font-stream PDF embedded font (sfnt) at offset 0xB1D8 16780 bytes
font_01_sfnt_off0000dc9a.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xDC9A 16792 bytes
font_02_sfnt_off0000f4b1.bin
110956eae01084aa6e1100987789fbd7d1158b1c25bd6c7511a011301fd4fb26
pdf-font-stream PDF embedded font (sfnt) at offset 0xF4B1 10760 bytes