Malicious PDF — malware analysis report

Static analysis result for SHA-256 c5fdb43776c31bf5…

MALICIOUS

PDF

79.4 KB Created: 2021-06-09 12:27:29 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: d90522aa118f6780f7764428bd6ef469 SHA-1: c3bdce90cafeae9dc9e22ffa66a38579e476381a SHA-256: c5fdb43776c31bf54740b5111a73de6f5bb836e9b321be7573a72b2b476a39f7
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains numerous links, many pointing to compromised WordPress sites, suggesting a link farm designed to redirect users to malicious content. The ClamAV detection and ML classifier strongly indicate malicious intent, likely phishing or malware distribution. The document body, though truncated, contains metadata suggesting it was generated by wkhtmltopdf, a tool sometimes used to create malicious PDFs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://allytemp.ru/uplcv?utm_term=lcm+of+3+numbers+worksheet
    • http://irmascaritasdejesus.org.br/wp-content/plugins/formcraft/file-upload/server/content/files/160afb6d79e5a5---52769363140.pdf
    • http://audiomaster.se/wp-content/plugins/formcraft/file-upload/server/content/files/16077959e0f771---47384427360.pdf
    • https://varbackaforskola.se/ckfinder/userfiles/files/magevovedov.pdf
    • http://steelbo.com/uploads/admins/u0/files/20210530103222.pdf
    • http://trackeg.com/en/wp-content/plugins/formcraft/file-upload/server/content/files/160abdb12e6001---gavupafido.pdf
    • http://bannails.com/fckeditor_userfiles/file/29920567016.pdf
    • http://westtech1963.com/clients/d/d4/d4250bc21dcbbf02d7f9bc68df143add/File/14928093120.pdf
    • https://thejinglelab.com/wp-content/plugins/super-forms/uploads/php/files/6dft49oi3rll01ilk3c4bgrp9f/86539331450.pdf
    • https://advicezone.org.uk/wp-content/plugins/super-forms/uploads/php/files/8qojkqvb9k09uouis4pqaqqf1l/makifuwelezeremafozasowof.pdf
    • https://cls-toronto.com/wp-content/plugins/super-forms/uploads/php/files/dc0984bc880d4a84ea516731d491fd62/parotujilulonowexutur.pdf
    • http://inewbus.com/wp-content/plugins/super-forms/uploads/php/files/p36gj7us1gchsmv4sm430pusp1/begoditi.pdf
    • http://0vote.com/ckfinder/files/rajosolabolo.pdf
    • https://caravanandre.it/wp-content/plugins/super-forms/uploads/php/files/791d86c94c5eb73affa43953ebfb0654/67370581090.pdf
    • https://kisikana.hr/userfiles/file/16152356134.pdf
    • https://getlovebooks.com/wp-content/plugins/super-forms/uploads/php/files/29b3a49645f3dce433a9b9d7fbee18fd/38844313371.pdf
    • https://stakeoutllc.com/wp-content/plugins/super-forms/uploads/php/files/80af39d2b0930805d9769c2aacd9019b/49834007748.pdf
    • http://abapaposentados.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16083390305112---78380990000.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • http://www.daltonmaag.com/
    • 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://scripts.sil.org/OFL

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ee77.bin
f4161d09689ddd503cda01668851518817f7fea489c59403e256901889997a52
pdf-font-stream PDF embedded font (sfnt) at offset 0xEE77 5116 bytes
font_01_sfnt_off0000ffcb.bin
9722f503f1451c98e016170f41295a50bcadd9d6913e9b37e037f3f0175a9a3a
pdf-font-stream PDF embedded font (sfnt) at offset 0xFFCB 10376 bytes
font_02_sfnt_off000122d3.bin
7f6049e5011acf0e8581793f2bc2bb947aac2929fdb77abc318b2a6155c1ef71
pdf-font-stream PDF embedded font (sfnt) at offset 0x122D3 4324 bytes