Malicious PDF — malware analysis report

Static analysis result for SHA-256 f51a99cfa6bfde95…

MALICIOUS

PDF

78.4 KB Created: 2021-06-08 05:19:48 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 3719513208045ddc95432ce2172dbb21 SHA-1: eea3952b151852ca48de65a99ec09db9ff91ac8e SHA-256: f51a99cfa6bfde959a9886287c15173aabfd55c4217dd94f70fc0d509444669a
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

This PDF file was flagged as malicious by both ML classifiers and ClamAV, indicating a high likelihood of malicious intent. The heuristic analysis revealed a significant number of external PDF links, suggesting a link farm or redirection scheme. The embedded URLs point to domains commonly associated with phishing and malware distribution, such as gimoguvi.ru and various weebly.com subdomains.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

Heuristics 5

  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://gimoguvi.ru/123?utm_term=grammatically+correct+sentences+worksheet
    • https://zujituxo.weebly.com/uploads/1/3/2/6/132681889/3590339.pdf
    • https://cdn-cms.f-static.net/uploads/4479932/normal_605524b87a04f.pdf
    • https://neposetami.weebly.com/uploads/1/3/4/6/134691268/wekim.pdf
    • https://cdn-cms.f-static.net/uploads/4480584/normal_60bec7dc48ed6.pdf
    • https://static.s123-cdn-static.com/uploads/4417530/normal_5fde746335eaa.pdf
    • https://static.s123-cdn-static.com/uploads/4501233/normal_5ff195673f757.pdf
    • https://cdn-cms.f-static.net/uploads/4418985/normal_6054f5dac6b28.pdf
    • https://duvirimak.weebly.com/uploads/1/3/4/6/134603536/b236c416672.pdf
    • https://runuxufugax.weebly.com/uploads/1/3/0/9/130969308/6124057.pdf
    • https://jobuvurivoko.weebly.com/uploads/1/3/2/6/132681743/3910378.pdf
    • https://jebupamix.weebly.com/uploads/1/3/6/0/136098333/4876055.pdf
    • https://cdn-cms.f-static.net/uploads/4470220/normal_600db8a6f0087.pdf
    • https://static.s123-cdn-static.com/uploads/4380869/normal_5ff1e67128a20.pdf
    • https://cdn-cms.f-static.net/uploads/4480389/normal_5fd6fe6115c65.pdf
    • https://static.s123-cdn-static.com/uploads/4530036/normal_5fc70e5ee2b9e.pdf
    • https://kusonanozeko.weebly.com/uploads/1/3/0/7/130775507/2691223.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://uploads.strikinglycdn.com/files/3514b496-b660-4b02-a9aa-e6e52f7d547a/piwawujiwedojozi.pdf
    • https://uploads.strikinglycdn.com/files/c94db0c4-2ea7-44b5-bab0-0c7ed26c8a6f/47686615069.pdf
    • https://uploads.strikinglycdn.com/files/eb497f4b-2ee4-43c7-903a-e5f62ab98a99/95720589585.pdf
    • https://uploads.strikinglycdn.com/files/942bf484-5f26-4884-af94-c3d5814908da/zumogofelelisiduloku.pdf
    • https://uploads.strikinglycdn.com/files/f6b3acf3-5ab8-467e-9285-07989dd908c0/honda_mower_hrr216k9vkaa_parts.pdf
    • https://uploads.strikinglycdn.com/files/c898d72c-862d-4699-803a-2a9b4ae54b3c/gluten_free_healthy_meal_ideas.pdf
    • https://uploads.strikinglycdn.com/files/8243f409-5e7d-4e5d-b425-27868fd8860a/kiwimitujulasud.pdf
    • 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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f52e.bin
f1d9e3ba8d4eb2945fddf11bed870ead7f6a98cf9d61122c8133d074baa051ac
pdf-font-stream PDF embedded font (sfnt) at offset 0xF52E 5328 bytes
font_01_sfnt_off0001073c.bin
755c9318db76c51136d287b188291ec30343f9530073a6868c8ed3943fba09ad
pdf-font-stream PDF embedded font (sfnt) at offset 0x1073C 10960 bytes