Malicious PDF — malware analysis report

Static analysis result for SHA-256 ac858c894a9dcffc…

MALICIOUS

PDF

69.7 KB Created: 2021-04-19 04:15:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-29
MD5: 6d84d812200b2c390464243602198ef8 SHA-1: 5708cd52d404fc48f6ad6c1a73f45f1b9ebde5b5 SHA-256: ac858c894a9dcffc22abfc3792a5afbf5c20c8791115dae674e966f89df91cb0
126 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. The document contains numerous embedded URLs, many of which point to disposable domains and are structured as link farms, a common tactic for distributing malware or phishing pages. While no scripts were explicitly extracted, the PDF structure and the nature of the URLs suggest an attempt to redirect the user to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • 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 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://portal-mysigma.com/system/files/student-proof/41429692510.pdf In PDF document text
    • https://ambrose.edu/sites/default/files/webform/juremetepatofuf.pdfIn PDF document text
    • https://www.enwidth.com/sites/default/files/webform/resumes/43403042061.pdfIn PDF document text
    • https://www.jwico.com/sites/default/files/webform/xojisipet.pdfIn PDF document text
    • http://www.grotekeukens.be/sites/default/files/webform/gmawards2018/41850888982.pdfIn PDF document text
    • https://www.ofalloncasting.com/sites/default/files/webform/geguridafaj.pdfIn PDF document text
    • https://www.newburghgroup.com/sites/default/files/webform/resumes/tikijoti.pdfIn PDF document text
    • https://www.dgs-interparts.be/sites/default/files/xufatonapa.pdfIn PDF document text
    • https://www.jwico.com/sites/default/files/webform/49109440539.pdfIn PDF document text
    • https://extranet.blanchisserie-toulousaine-de-sante.com/sites/extranet.blanchisserie-toulousaine-de-sante.com/files/documents/justificatifs/vinoku.pdfIn PDF document text
    • http://oaklandchildcare.org/sites/default/files/webform/ponezilineg.pdfIn PDF document text
    • http://cicatsalud.com/html/sites/default/files/webform/86929885116.pdfIn PDF document text
    • https://www.mothercare.ro/sites/default/files/webform/resumes/49428740932.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.daltonmaag.com/In PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/6naE_Nh8_CY/uplcv?utm_term=introduction+to+econometrics+3rd+edition+solutions+chapter+6PDF link annotation
    • 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000c4da.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC4DA 5452 bytes
SHA-256: 247128c09e6c10e7e155c55ba9cf9b0d7cc46c25783ca8223034d716a9a99485
font_01_sfnt_off0000d721.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD721 10648 bytes
SHA-256: b38d1c099f24148e47a1f3c6ce7f8b0e5002f951bd4bea3e017af8f87214ac56
font_02_sfnt_off0000fb69.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFB69 4324 bytes
SHA-256: 7f6049e5011acf0e8581793f2bc2bb947aac2929fdb77abc318b2a6155c1ef71

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