Malicious PDF — malware analysis report

Static analysis result for SHA-256 63e4b7b69a39503d…

MALICIOUS

PDF

74.1 KB Created: 2021-04-05 22:10:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 6f5d5b9300ddb0f7c3fbe57e07186462 SHA-1: b9a8b2c6c0a504ae47982446adae0e4ff68fb335 SHA-256: 63e4b7b69a39503dba05ad1576f1e3427c61e34c8f1edbf8cdc8601b1d721879
156 Risk Score

Malware Insights

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

The PDF file contains a large number of external links, many pointing to S3 buckets and other cloud storage services, suggesting a link farm or a distribution mechanism for further payloads. The ClamAV detection and ML classifier strongly indicate malicious intent, specifically identified as a phishing trojan. The embedded URL `https://dafemum.ru/123?utm_term=comparative+superlative+worksheet+grade+3` is likely the primary lure, directing users to a malicious site.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

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://dafemum.ru/123?utm_term=comparative+superlative+worksheet+grade+3
    • https://cdn-cms.f-static.net/uploads/4387031/normal_6019f1e088718.pdf
    • https://static.s123-cdn-static.com/uploads/4426966/normal_5fdfae7e8182c.pdf
    • https://static.s123-cdn-static.com/uploads/4377662/normal_60025ae0069b5.pdf
    • https://static.s123-cdn-static.com/uploads/4450251/normal_600221e0dccb4.pdf
    • https://cdn-cms.f-static.net/uploads/4420248/normal_5fd93248c3855.pdf
    • https://cdn-cms.f-static.net/uploads/4499635/normal_603979bbc1da6.pdf
    • https://static.s123-cdn-static.com/uploads/4401989/normal_5ff261e087eeb.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • http://www.daltonmaag.com/
    • https://s3.amazonaws.com/fejififimaketo/lupotegerevokamijavutufa.pdf
    • https://s3.amazonaws.com/xepululejiwof/sibifegiwuwet.pdf
    • https://s3.amazonaws.com/jarirotexab/bhakti_songs_free_._com.pdf
    • https://s3.amazonaws.com/nakuzafol/98741072982.pdf
    • https://s3.amazonaws.com/marimejerebo/the_key_moment_meaning.pdf
    • https://2ac8321c-28d8-41c8-ac7a-99137a6fe030.filesusr.com/ugd/157ee0_df17275921524bf49fb3940a3db29424.pdf?index=true
    • http://resisimokopi.epizy.com/auto_format_visual_studio_c.pdf
    • https://s3.amazonaws.com/resisuna/que_es_el_local_guides.pdf
    • http://magomodatibotu.epizy.com/happy_birthday_to_you_free.pdf
    • https://s3.amazonaws.com/xunilukegez/ejercicios_de_porcentajes.pdf
    • https://16564176-4c62-44d7-82e3-1dea6b832d73.filesusr.com/ugd/5e57cf_2d81290ddb5d4ace816ad489efc1fceb.pdf?index=true
    • https://s3.amazonaws.com/zepifudoxapo/90758023462.pdf
    • https://6c8ebe11-725c-420b-823a-68bc39d02ad2.filesusr.com/ugd/3e87bf_64118400ff8243db908eff22ec7a24e3.pdf?index=true
    • https://s3.amazonaws.com/kelukakeb/geninerupidox.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d4a1.bin
c7285c12575770d14b16fc5735e3ae34f7d7fa50491b0867338352722935f611
pdf-font-stream PDF embedded font (sfnt) at offset 0xD4A1 5552 bytes
font_01_sfnt_off0000e79f.bin
e77cfa913565a078f26c3a86a252ab2fcf5d91dda5b497d9d86fd2020b2292e8
pdf-font-stream PDF embedded font (sfnt) at offset 0xE79F 10928 bytes
font_02_sfnt_off00010cd0.bin
9f355172d696dda274cac500966718f112ce76951f19577ac4888987ea6471b2
pdf-font-stream PDF embedded font (sfnt) at offset 0x10CD0 4324 bytes