Malicious PDF — malware analysis report

Static analysis result for SHA-256 81531d2e88510e2c…

MALICIOUS

PDF

66.8 KB Created: 2020-11-13 03:46:38 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: d23cb78cdff3f345c961f45473e4df90 SHA-1: bda7e020f51168302dba70a8717b79e7b4a58162 SHA-256: 81531d2e88510e2c043c501c17123ac745b13ac832c9cab90a3b342cd0bf4f21
156 Risk Score

Malware Insights

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

The sample is identified as malicious by multiple heuristics and a ML classifier, with ClamAV detecting it as a phishing trojan. It contains a large number of external links, many pointing to PDF files hosted on file-sharing services, suggesting a link farm or redirection mechanism. One of the extracted URLs, 'https://traffset.ru/123?utm_term=lb+ft3+to+kn+m3', is likely part of the initial lure or redirection chain. No scripts were extracted, but the PDF structure and numerous external links indicate an attempt to direct the user to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://traffset.ru/123?utm_term=lb+ft3+to+kn+m3
    • https://vajibudutoneraz.weebly.com/uploads/1/3/4/3/134345344/bolovibirob.pdf
    • https://cdn-cms.f-static.net/uploads/4368265/normal_5f930e748676a.pdf
    • https://pinukozemaf.weebly.com/uploads/1/3/4/7/134713375/4846678.pdf
    • https://cdn-cms.f-static.net/uploads/4367290/normal_5f89f95cdf0ef.pdf
    • https://masogipu.weebly.com/uploads/1/3/1/6/131606875/5e9ca1a815f7916.pdf
    • https://cdn-cms.f-static.net/uploads/4374533/normal_5f92dd1e5ae52.pdf
    • https://wawaxotev.weebly.com/uploads/1/3/4/3/134368025/2492454.pdf
    • https://pabeliribid.weebly.com/uploads/1/3/4/3/134384766/kuremulexugex_gofedikegabopav.pdf
    • https://cdn-cms.f-static.net/uploads/4450639/normal_5f9f81d3b0d3d.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://uploads.strikinglycdn.com/files/dc6b443c-7ae4-497f-9091-929c2d3553a2/60287802932.pdf
    • https://uploads.strikinglycdn.com/files/b94813f0-f0ed-46f1-8745-18c4179177fb/kodotaboka.pdf
    • https://uploads.strikinglycdn.com/files/5dc0287c-b52e-4543-9ed6-ec811efc35d9/tileboba.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_off0000c924.bin
65ef7ff121fa33f80b3635570b224bf76ee1cc2e564fd8dbbeaced534224f593
pdf-font-stream PDF embedded font (sfnt) at offset 0xC924 4704 bytes
font_01_sfnt_off0000d92b.bin
e78702a43ad4b77bee634f57a5f6fb1ccc6b2a908370b8c6186348cae8fc06e6
pdf-font-stream PDF embedded font (sfnt) at offset 0xD92B 11220 bytes