Malicious PDF — malware analysis report

Static analysis result for SHA-256 9f478c32e97e79fa…

MALICIOUS

PDF

88.3 KB Created: 2021-09-14 00:44:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: b735a6b5611022078092a6bc4e9de8df SHA-1: 35f88e2c70c02d355b16d501ecf7ae71cc670086 SHA-256: 9f478c32e97e79fa140c85e40afbf2ac111771fe91c4c56e15bac6a9da1f7fe1
156 Risk Score

Malware Insights

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

The PDF was flagged by multiple heuristics as a link farm, with several URLs pointing to compromised WordPress upload storage and disposable hosting. The ML classifier and ClamAV also identified it as malicious, specifically a phishing trojan. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather to host links.

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 http://a2itsolutions.com/chop/multimedia/userfiles/file/darafi.pdf
    • https://www.aicsmindia.org/ckfinder/userfiles/files/wibesefuvutarofoseferez.pdf
    • http://pereplanirovkaoblast.ru/pict/file/40226075395.pdf
    • https://vargyasnekonyveles.hu/kepek/other/file/37852980768.pdf
    • http://gowowdeli.com/uploads/files/nupuwexawuvupevuremur.pdf
    • http://intrinhgia.com/admin/webroot/upload/image/files/64266858182.pdf
    • http://around-sicily.net/userfiles/file/wekurijozinojivumofoji.pdf
    • http://colantuono.it/userfiles/files/xawus.pdf
    • https://sandp-engineering.com/ckfinder/userfiles/files/kisuneriweladejebogotuxor.pdf
    • http://ksiclubbiz.ksiclub.org/svnprojects/DHD/Source/images/files/41027370279.pdf
    • http://informerfitness.com/wp-content/plugins/super-forms/uploads/php/files/cf6617c8ddfd3693597de4b141dfc054/10240119307.pdf
    • http://www.thebetterinsurance.com/wp-content/plugins/formcraft/file-upload/server/content/files/161382976a22c5---72286397076.pdf
    • http://kingkady.cn/uploadfile/files/jasojebovitonuzik.pdf
    • https://alohasafaris.com/files/guniwubevixosujutokumo.pdf
    • http://longruiglass.com/ckfinder/userfiles/files/20210904_065344.pdf
    • http://hvezda-pardubice.cz/files/file/69864144321.pdf
    • https://www.tonygssoulfood.com/wp-content/plugins/super-forms/uploads/php/files/3984d57e1f89b933124294b91c5d40a4/gaxopebofugiridifu.pdf
    • https://digireg.org/upload/tivimelalurowim.pdf
    • http://nsk-nalogov.net/upload/files/badizogajafurazu.pdf
    • http://www.appsolutely.sg/wp-content/plugins/formcraft/file-upload/server/content/files/16132cb80f405d---91604225293.pdf
    • http://haai.org/upload/file/18398809797.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/YTWXjIUwRh0/uplcv?utm_term=top+serp+tracker
    • 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_off0000f77d.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xF77D 16792 bytes
font_01_sfnt_off00010f8f.bin
3a2e067b3c5300d6c8ca2b2b14361e78a6dcf4ed92c4f8603f9b889d1ca7f904
pdf-font-stream PDF embedded font (sfnt) at offset 0x10F8F 17520 bytes
font_02_sfnt_off00013d21.bin
17426bd98481e95dd297c0c16c4255680ff7b1ef7258a458912f907558649df2
pdf-font-stream PDF embedded font (sfnt) at offset 0x13D21 10180 bytes