Malicious PDF — malware analysis report

Static analysis result for SHA-256 81cc7cf521a400c5…

MALICIOUS

PDF

80.3 KB Created: 2021-04-01 12:23:01 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: a7507061744edae43314cc87e7130173 SHA-1: 76500650c53649c01c3b3415b8478d54ba4c810d SHA-256: 81cc7cf521a400c5766426a38e59e4016c1cb0a407016ccbc2d078b6c25a5a84
156 Risk Score

Malware Insights

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

The PDF contains a large number of external links, many pointing to Weebly-hosted PDFs, indicative of a link farm. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or SEO abuse. While no scripts were explicitly extracted, the PDF structure and embedded URLs are sufficient to infer a malicious purpose.

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://resalured.ru/award?keyword=broad+based+black+economic+empowerment+pdf
    • https://kobuxomibusopi.weebly.com/uploads/1/3/4/6/134609859/3547062.pdf
    • https://pewoguliburutoj.weebly.com/uploads/1/3/4/2/134234653/2726301.pdf
    • https://zujuwedidikaf.weebly.com/uploads/1/3/4/3/134375258/vifof.pdf
    • https://vuxozajuje.weebly.com/uploads/1/3/1/3/131379873/mowuji.pdf
    • https://fanarise.weebly.com/uploads/1/3/4/3/134377412/riziwikebi.pdf
    • https://xaredeni.weebly.com/uploads/1/3/1/8/131871979/gotuzibolajuli-gubajo.pdf
    • https://nolaxefipox.weebly.com/uploads/1/3/4/7/134740184/8999060.pdf
    • https://kubetezoruxi.weebly.com/uploads/1/3/4/6/134600107/64ca2dd34685.pdf
    • https://tunupufimudodo.weebly.com/uploads/1/3/4/3/134324073/5ef83c4c28d.pdf
    • https://luzulobopado.weebly.com/uploads/1/3/2/6/132681737/5326765.pdf
    • https://wezenojaze.weebly.com/uploads/1/3/4/0/134095843/8317215.pdf
    • https://gonuvogizup.weebly.com/uploads/1/3/1/8/131857562/5284043.pdf
    • https://gogesatita.weebly.com/uploads/1/3/4/3/134321397/nobewusu.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • http://www.daltonmaag.com/
    • https://s3.amazonaws.com/jusagi/grocery_list_maker_excel_template.pdf
    • https://uploads.strikinglycdn.com/files/1e3a4541-71e0-40c4-b01e-2f30046fa4d0/faxupovefuzivuno.pdf
    • https://uploads.strikinglycdn.com/files/ee6b3b5f-0908-4096-a14b-674990debcb8/diary_of_a_wimpy_kid_the_last_straw_audiobook_free_download.pdf
    • https://uploads.strikinglycdn.com/files/fe70decf-b9bc-46ac-b84a-ccfafb305f02/how_to_start_bread_bakery_business_in_nigeria.pdf
    • https://uploads.strikinglycdn.com/files/14ef85d0-c271-4dba-993e-352760f30552/how_to_fall_asleep_without_melatonin.pdf
    • https://s3.amazonaws.com/nevowimo/35380600146.pdf
    • https://uploads.strikinglycdn.com/files/70ce0890-c7a6-4ec6-ba91-5a0a0501dc91/69417803362.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_off0000ef5c.bin
c71ffdff30d05d98a37482aa6b529859f9b7a1944be1fc5fc35a11484f6b927d
pdf-font-stream PDF embedded font (sfnt) at offset 0xEF5C 5436 bytes
font_01_sfnt_off000101c7.bin
efb10bb7f80351fb93f75eee744aac0b92dfd00e54ebadb11272c6f6eedf4b6f
pdf-font-stream PDF embedded font (sfnt) at offset 0x101C7 10536 bytes
font_02_sfnt_off000125c1.bin
0d0f64e27578eb124b8bc81c7eceacdd166e22eddd95c81328e9fbd7de2a6333
pdf-font-stream PDF embedded font (sfnt) at offset 0x125C1 4324 bytes