Malicious PDF — malware analysis report

Static analysis result for SHA-256 a761b5e5c5d82137…

MALICIOUS

PDF

83.0 KB Created: 2021-04-03 05:45:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-24
MD5: 73e9fb594899b090730c6e5a970a3f53 SHA-1: 23731d56089c58736aa27b3641946c7d7c4152df SHA-256: a761b5e5c5d82137d5d80b0b7e8093e6e57ed8c82a504e648a0b0966d437cce0
186 Risk Score

Malware Insights

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

This PDF file was identified as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains a link farm with numerous external URLs, including one pointing to 'xajibur.ru', suggesting it's used for traffic generation or distributing further malware. The document body, though heavily obfuscated, contains text related to rating scales, likely a lure to entice users to click the embedded links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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://xajibur.ru/strik?utm_term=why+use+a+5+point+rating+scale PDF link annotation
    • https://cdn.sqhk.co/netesatova/71jfijz/33888392503.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4392237/normal_6022d17f227fd.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4377381/normal_5ff8fcd9b972e.pdfIn PDF document text
    • https://cdn.sqhk.co/guranotup/jhigib6/61386060170.pdfIn PDF document text
    • https://cdn.sqhk.co/dumudegurit/ifKibgh/happy_number_painting_by_numbers.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4379053/normal_5fc953a27dadf.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4459483/normal_5fc5a310cd272.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4419826/normal_60564d1f9cb5a.pdfIn PDF document text
    • https://cdn.sqhk.co/xusozapovu/JHKhiij/31516798444.pdfIn PDF document text
    • https://cdn.sqhk.co/zupololano/l5nie53/6952315591.pdfIn PDF document text
    • https://cdn.sqhk.co/deloreba/xEUUhic/xosutalumetosadizob.pdfIn PDF document text
    • https://cdn.sqhk.co/jinubodilev/MFpSoih/escape_alcatraz_metal_detector.pdfIn PDF document text
    • https://cdn.sqhk.co/tekuligote/V1Ahgjc/83569966093.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://uploads.strikinglycdn.com/files/6514cd23-3f15-47f4-93e6-641b9831ada1/91626375987.pdfIn PDF document text
    • https://d429d46a-6203-486b-8c9d-ede5597e1383.filesusr.com/ugd/419b00_f3976a36b9524a19bd3b821ea4e8be2a.pdf?index=trueIn PDF document text
    • https://1ec9b6e7-17eb-4e1e-a994-ba5ce4cbdb7c.filesusr.com/ugd/d4a9d6_d0157d51ca904f3e97a6e2b125b66e71.pdf?index=trueIn PDF document text
    • https://9e269ae7-c3cf-4b9f-bde2-1d9be064b7bf.filesusr.com/ugd/139869_1ec9ec2e00644f739c3d577e73170b37.pdf?index=trueIn PDF document text
    • https://e2604e0b-f95a-4acb-b53f-a7db3827b2a1.filesusr.com/ugd/225520_484f91df062147c6b2b8014a99c73cbd.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/3891ce0b-3678-45db-a0a5-b28c05f2c6e0/xarewamimibuxoxulusowitaz.pdfIn PDF document text
    • https://ac911ccd-a574-46a9-bbb3-57bb927ff796.filesusr.com/ugd/2735c9_03be41499e6349ec95a6de9ab682e14f.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/e2f4559d-0e5b-4a7e-b44d-f9112aacf5a5/vasefezapof.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/50b70b73-24d1-4633-b641-036258d7bdba/67147580337.pdfIn PDF document text
    • https://61090d85-22e6-4724-b969-52a17785150c.filesusr.com/ugd/952c2e_84840de06d0c4537b2641deed6e7dc68.pdf?index=trueIn PDF document text
    • https://uploads.strikinglycdn.com/files/bc724efe-4c73-4cc1-95c9-cbebc2fe77d9/siroxulatitalitexi.pdfIn PDF document text
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00010482.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10482 5436 bytes
SHA-256: b6e16e1984c75ac92b76d62528beba07213f22448fc89d04295d7d2c04c18bd3
font_01_sfnt_off00011714.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11714 11588 bytes
SHA-256: 6260b8089dfa9ac8f261fd3ce2531b36bcfe70d2a41e72706bfe38922004b523

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