Malicious PDF — malware analysis report

Static analysis result for SHA-256 2555ead414d0a8ee…

MALICIOUS

PDF

80.8 KB Created: 2021-03-14 21:40:58 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: b72ac463eaf46264f2cfa3132b9e618f SHA-1: 2b7ccaeef070c8ab9fa5affcf87e2a552f59d9aa SHA-256: 2555ead414d0a8eedf62b250ecd54242cba18ad1a8b8e186e4e56804037911a8
156 Risk Score

Malware Insights

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

The PDF file was flagged as malicious by ML classifiers and ClamAV, specifically identified as a phishing trojan. It contains numerous external links, with a primary URL pointing to a link farm designed to redirect users to other PDF documents. The document body, though heavily obfuscated, suggests a lure related to educational worksheets.

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-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://mezovuduw.ru/award?keyword=reading+comprehension+worksheets+pdf+6th+grade
    • https://static.s123-cdn-static.com/uploads/4387033/normal_5fefc6ed69a07.pdf
    • https://cdn-cms.f-static.net/uploads/4412758/normal_6022232eeb77b.pdf
    • https://static.s123-cdn-static.com/uploads/4444626/normal_6007a62053995.pdf
    • https://cdn-cms.f-static.net/uploads/4388406/normal_5fe802817bdbc.pdf
    • https://cdn-cms.f-static.net/uploads/4465136/normal_6016e109dec24.pdf
    • https://cdn.sqhk.co/ludozenidi/wc5gfgf/72116043443.pdf
    • https://cdn-cms.f-static.net/uploads/4408482/normal_6022d077afed7.pdf
    • https://cdn.sqhk.co/zenekukera/fihhVhd/57910116751.pdf
    • https://cdn.sqhk.co/wugolekufo/hdiemsZ/77590816708.pdf
    • https://cdn.sqhk.co/napumefu/Mihiaie/attendance_tracking_app.pdf
    • https://cdn-cms.f-static.net/uploads/4455370/normal_601524de7f828.pdf
    • https://cdn.sqhk.co/xebosulog/Egchjjf/pigalamidaw.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • http://www.daltonmaag.com/
    • https://551f0ad2-75d1-4009-b90b-2f3e3e20230b.filesusr.com/ugd/c2bf0a_abbfa488a0964cf78315627092f91851.pdf?index=true
    • https://7e073981-ad1c-4081-8dc0-76946ba36063.filesusr.com/ugd/c4f63d_d828e64a51144d6bbd4bf837724f471f.pdf?index=true
    • https://1350f94c-8d6f-42b4-8351-24983ad6a49a.filesusr.com/ugd/4aae87_9049cd52a9464f139f3e6f972aea5643.pdf?index=true
    • https://07f52280-50dc-49c2-beec-a2e30bf849d0.filesusr.com/ugd/7b8f90_c3346c3239a048178df4dbdb793cef14.pdf?index=true
    • 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_off0000f0a1.bin
ee6c101fe3a641cb960856fbc8b6ef9d00ac3adce2eeb641bb8f47d5c4965c0d		 pdf-font-stream PDF embedded font (sfnt) at offset 0xF0A1 5640 bytes
font_01_sfnt_off000103b2.bin
b606808900cde26b47e012b70000384dc4a2df9227f358189c8c8f0004dff5b5		 pdf-font-stream PDF embedded font (sfnt) at offset 0x103B2 10744 bytes
font_02_sfnt_off00012824.bin
1158d95dac44631f497756703988ba3645251422e7ff0015d3fca430225e7c3e		 pdf-font-stream PDF embedded font (sfnt) at offset 0x12824 4324 bytes

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