Malicious PDF — malware analysis report

Static analysis result for SHA-256 ecb99dfc150f920c…

MALICIOUS

PDF

77.7 KB Created: 2021-04-23 19:04:09 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-22
MD5: 02b9729f84fa64575e8f558eaa206056 SHA-1: 238819a994fdefa3caa6cd00f383d6064ec46807 SHA-256: ecb99dfc150f920c7b9cc85e1f0c367ba42cbada055ad990ef00a0823f573c85
126 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs, many of which point to seemingly legitimate domains but are structured as webform submissions, suggesting a phishing or credential harvesting attempt. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic indicates a pattern of using numerous distinct hosts to obscure malicious activity.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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 http://www.pbttphtk.gov.my/sites/default/files/webform/1232685222.pdf In PDF document text
    • https://ambrose.edu/sites/default/files/webform/49323480199.pdfIn PDF document text
    • https://www.uts.cw/sites/default/files/webform/bofuwidesuxugebogaxa.pdfIn PDF document text
    • https://www.enwidth.com/sites/default/files/webform/resumes/79062027218.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/61943826361.pdfIn PDF document text
    • https://www.blplegal.com/sites/default/files/webform/piselusani.pdfIn PDF document text
    • https://www.woonsocketri.org/system/temporary/webform/danajon.pdfIn PDF document text
    • https://www.blplegal.com/sites/default/files/webform/3097059720.pdfIn PDF document text
    • https://www.blplegal.com/sites/default/files/webform/54305505708.pdfIn PDF document text
    • http://pilgrimland.com/sites/default/files/webform/resume-uploads/jitebetususi.pdfIn PDF document text
    • http://www.grotekeukens.be/sites/default/files/webform/gmawards2018/dufadurelabakugozuku.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/cv9VXjIrmdE/uplcv?utm_term=organic+chemistry+definition+biologyPDF link annotation
    • https://ubmemeaensoprod.s3.amazonaws.com/ifsec_international/call_for_papers/2021/03/65910459182.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_off0000ef60.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEF60 5704 bytes
SHA-256: 3abd1198e4dfc402b8726ebd8879ee4cc941d1d6994d902c699e34310b20672d
font_01_sfnt_off000102a1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x102A1 11216 bytes
SHA-256: 086b23fe41922bd289d021f45a942fe1ff6b311814319892b2d6ef08d44dca50

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