Malicious PDF — malware analysis report

Static analysis result for SHA-256 f9c0b55864a106f4…

MALICIOUS

PDF

74.8 KB Created: 2021-09-16 09:57:12 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 6e85c5e17dbe4fb3357c122abe7a229a SHA-1: e34d84ef44ecc4bd3546086e69b744132b03a324 SHA-256: f9c0b55864a106f47a6fd209af000ddb04b842a5d0cbc23fba06613067ff36a4
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file contains embedded JavaScript, which is a common technique for exploiting PDF vulnerabilities or redirecting users. Multiple heuristics indicate the PDF acts as a link farm, pointing to various external URLs hosted on potentially compromised or disposable domains. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or distributing further malware.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

Heuristics 7

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://stkvn.ru/wp-content/plugins/super-forms/uploads/php/files/f3733818476b0ac373820343a104d1fe/nexedekijugodudagogado.pdf
    • https://andhimazhai.com/images/files/95217149532.pdf
    • https://dichvuhappyhouse.com/upload/files/30219334427.pdf
    • http://snnet.kr/board_pds/fckeditor/2021/09/file/zekubemob.pdf
    • http://tnslib.tools/userfiles/files/36312741584.pdf
    • https://registracijakoncar.com/webroot/js/ckfinder/userfiles/files/letadefonopes.pdf
    • http://grupomarsamo.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613e3d4c8368e---75638739745.pdf
    • http://jamesandsons.ca/userfiles/file/42542074640.pdf
    • http://websurin.net/UserFiles/File/14338078233.pdf
    • http://canshu.dlzj.net/upload/files/20210914005225398644.pdf
    • http://studio5r.com/userfiles/files/16815989102.pdf
    • http://dfwsedan.com/nbloom/fckuploads/file/vejudewisosebigojukofomaz.pdf
    • http://csc0851.com/userfiles/file/20210909061619_cf5190.pdf
    • https://lynnesnaturaltreats.com.au/wp-content/plugins/super-forms/uploads/php/files/361ad08bcc9450e82658ceeca1dea622/99672874346.pdf
    • https://rawoctane.com/uploads/file/56202749525.pdf
    • https://pikhospital.com/ck_uploads/uploads/files/4135090708.pdf
    • https://ostrichtours.com/ckfinder/userfiles/files/35054347251.pdf
    • http://sieuthimaynhapkhau.com/upload/files/virilerevufapukotawilogef.pdf
    • http://coumert.com/images/file/dubamuvanag.pdf
    • http://tea-ra.com/user_data/upload/save_image/files/bejivokimafudega.pdf
    • http://iberia-ex.com/images/blog/file/gerobomabo.pdf
    • http://www.jindatunnel.com/up_files/file/gafofepibo.pdf
    • https://flour.co.uk/ckfinder/userfiles/files/xagogoxovapulidimujo.pdf
    • http://marcus-1.com/FileData/ckfinder/files/20210915_BD142EE84AB73CE8.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/LPIa9PGmDLg/uplcv?utm_term=stream+champ+apk+for+android
    • 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_off0000c10c.bin
7969efc64895572332548dfa396055270dbaae8148683e6e6fc3ca894d12a3f1
pdf-font-stream PDF embedded font (sfnt) at offset 0xC10C 16920 bytes
font_01_sfnt_off0000ecaf.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xECAF 16792 bytes
font_02_sfnt_off000104c6.bin
cceb6c04ce9b5331992cd79fdedc1eb2e085e508f1f03900cb0d8b2be66a57c7
pdf-font-stream PDF embedded font (sfnt) at offset 0x104C6 10836 bytes