Malicious PDF — malware analysis report

Static analysis result for SHA-256 b4661df996c7f29d…

MALICIOUS

PDF

79.4 KB Created: 2021-05-19 20:49:45 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-27
MD5: f00854c76d1c66cb5657acbfd8f7987a SHA-1: ef5605047a313561050024f97f420f7a8da3fd55 SHA-256: b4661df996c7f29d91f962b6eef186138bba809b050d2b6af963504cccc90b58
186 Risk Score

Malware Insights

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

The PDF contains a large number of external links, many hosted on disposable domains, indicating a link farm designed to redirect users. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or distributing further malware. The presence of embedded URLs and the overall structure point towards a spearphishing attachment attack vector.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

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
  • 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.
  • 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://jacksth.ru/strik?utm_term=amazon+kindle+mod+apk+moddroid PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4388422/normal_603cfdf89f1d2.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4378161/normal_601c9708294cb.pdfIn PDF document text
    • https://lotuliwupufak.weebly.com/uploads/1/3/4/8/134873452/c63e1c85.pdfIn PDF document text
    • https://wanuwajazil.weebly.com/uploads/1/3/4/8/134899981/9742308.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4476765/normal_5fdee046c0f88.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4421207/normal_6039604426f25.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4419193/normal_60294e4524934.pdfIn PDF document text
    • https://linulozaf.weebly.com/uploads/1/3/1/4/131437298/gixeg.pdfIn PDF document text
    • https://vakilelem.weebly.com/uploads/1/3/1/3/131379598/4820379.pdfIn PDF document text
    • https://zavexirated.weebly.com/uploads/1/3/2/6/132695663/topugexil_zajatubu.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4474989/normal_6029ce731426a.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4454277/normal_60149130db9c8.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4382614/normal_602df4b6aaf09.pdfIn PDF document text
    • https://nutikatike.weebly.com/uploads/1/3/4/6/134601603/xiniwunipuvi-gadupexososedi-tumipagutenaz.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4484618/normal_5fe435034c9e5.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4494673/normal_601c7b39ce486.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4476757/normal_5fe54f325b9b5.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4369908/normal_602c9b0749949.pdfIn PDF document text
    • https://tonusawojojumo.weebly.com/uploads/1/3/1/3/131384735/d0ae9ab.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4501804/normal_606925de894ed.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4415051/normal_6015589823cc4.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://s3.amazonaws.com/piradi/why_is_my_grill_not_heating_up.pdfIn PDF document text
    • https://s3.amazonaws.com/zupenafud/nejewagatelodogo.pdfIn PDF document text
    • https://s3.amazonaws.com/tobito/masulixufolipe.pdfIn PDF document text
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f6e1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF6E1 5032 bytes
SHA-256: 2c2725864c93248d108a64dffb268b4f2708813215b7c98528d70501f2da7dd2
font_01_sfnt_off000107e9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x107E9 12812 bytes
SHA-256: 9433d1790773e0a6317b74bc4184f9964da3b993ed435899ba1669062dc58e28