Malicious PDF — malware analysis report

Static analysis result for SHA-256 2bbb2303643aae55…

MALICIOUS

PDF

76.2 KB Created: 2021-03-24 06:56:12 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 6464359f8e5f2fc5ac796a99f78ea0d8 SHA-1: a35fa0765936856f3011e37213ac3b726e5a828c SHA-256: 2bbb2303643aae5510a248650588d920459dbf8ece68bc957161c6e481ab2c8a
156 Risk Score

Malware Insights

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

The file was detected as malicious by ClamAV and an ML classifier, and exhibits characteristics of a PDF link farm. It contains a large number of external URIs, with a critical heuristic identifying it as a small PDF with a mass external PDF link farm. The primary malicious URL identified is https://nipisod.ru/123?utm_term=do+cumulonimbus+clouds+form. No scripts were extracted, but the presence of numerous external links suggests a phishing or SEO spam campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://nipisod.ru/123?utm_term=do+cumulonimbus+clouds+form
    • https://cdn-cms.f-static.net/uploads/4495855/normal_5fe74b9dd002c.pdf
    • https://cdn-cms.f-static.net/uploads/4482403/normal_5fdbc2bdd84a9.pdf
    • https://cdn-cms.f-static.net/uploads/4466376/normal_602e327034bbf.pdf
    • https://cdn-cms.f-static.net/uploads/4499673/normal_60299154a33d4.pdf
    • https://static.s123-cdn-static.com/uploads/4427514/normal_6000c930994cc.pdf
    • https://static.s123-cdn-static.com/uploads/4421460/normal_5ff4e07776a7b.pdf
    • https://dagazafija.weebly.com/uploads/1/3/1/4/131484603/zasetumo.pdf
    • https://cdn-cms.f-static.net/uploads/4408713/normal_601b369a861b3.pdf
    • https://bumarotijij.weebly.com/uploads/1/3/4/6/134688095/842ad3.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://2aa89031-56ac-4de1-b828-aabe99840ec8.filesusr.com/ugd/cf14a4_200edd02eb91445781d6378e3a4a3804.pdf?index=true
    • https://s3.amazonaws.com/lumixi/chem_tech_100_manual.pdf
    • https://s3.amazonaws.com/sifawekujiki/how_to_change_toner_cartridge_in_brother_dcp_7040.pdf
    • https://0296ecfc-28ae-4fa5-925c-67a25994cace.filesusr.com/ugd/c88839_fbfd144c5abf433d85f587bfe49c00a7.pdf?index=true
    • https://s3.amazonaws.com/perurulexi/72032660780.pdf
    • https://s3.amazonaws.com/sitozi/1919208339.pdf
    • https://s3.amazonaws.com/jubiferekaka/tilurevetaruxera.pdf
    • https://4f870d4f-701c-4ec6-bbb3-7277acc5528a.filesusr.com/ugd/fdcb8d_31d6d3080f1440d9a0d782f1b61dbc34.pdf?index=true
    • https://s3.amazonaws.com/nafibanefexex/proxy_server_refusing_connections_tor_android.pdf
    • https://s3.amazonaws.com/wovugi/movimiento_rectilineo_uniforme_ejemplos_con_dibujos.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_off0000eb9e.bin
4977f146e8e909414b2c7a2678448d8156830671151fa6ceaafb3105d66ffe72		 pdf-font-stream PDF embedded font (sfnt) at offset 0xEB9E 5096 bytes
font_01_sfnt_off0000fcde.bin
22a19971ffb7a0bd029c841fffea2f1c13e465492162574682440d84e496dede		 pdf-font-stream PDF embedded font (sfnt) at offset 0xFCDE 11196 bytes

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