Malicious PDF — malware analysis report

Static analysis result for SHA-256 8e30dbb26179f47d…

MALICIOUS

PDF

77.8 KB Created: 2021-04-16 06:28:12 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-14
MD5: cac27db36fbe03f5e81274166d24f44b SHA-1: 9dacb8c27119d12dcfc435c374fbe3ee5dafa947 SHA-256: 8e30dbb26179f47db0aaa82fa68d4ebefbaf488e862b39f2dcd87eee7079de3e
126 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, indicating a high likelihood of malicious intent. The document body, though heavily obfuscated, contains references to 'wkhtmltopdf' and a date, suggesting it was generated programmatically. The presence of numerous embedded URLs, many pointing to seemingly legitimate domains but within specific 'webform' directories, suggests a link farm or phishing lure. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic further supports this, indicating an attempt to disguise malicious links within a large number of external references.

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 https://ambrose.edu/sites/default/files/webform/durigoxilakomisi.pdf In PDF document text
    • https://www.woonsocketri.org/system/temporary/webform/viwubamonutimujogigifowi.pdfIn PDF document text
    • https://www.blplegal.com/sites/default/files/webform/pifijolaj.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/52499587618.pdfIn PDF document text
    • https://www.pharoxglobal.com/sites/default/files/webform/7322176875.pdfIn PDF document text
    • https://www.natsihwa.org.au/sites/default/files/webform/17947704001.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/9027254294.pdfIn PDF document text
    • http://portal-mysigma.com/system/files/student-proof/tevesifisota.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/skout/mBVl/~3/LPIa9PGmDLg/uplcv?utm_term=how+do+they+fix+a+frozen+shoulderPDF link annotation
    • https://community.princeton.edu/system/files/webform/13590028771.pdfIn PDF document text
    • https://community.princeton.edu/system/files/webform/jidubiziro.pdfIn PDF document text
    • https://umatter.princeton.edu/system/files/webform/requests/roporopapoviz.pdfIn PDF document text
    • https://lib.asu.edu/system/files/webform/90369837207.pdfIn PDF document text
    • https://www.ice.cam.ac.uk/sites/www.ice.cam.ac.uk/files/webform/68876097481.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_off0000f381.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF381 5268 bytes
SHA-256: d6c98b5206a902689fb71db2d72c12e64ec41203b2e1882e24303cf8104a0690
font_01_sfnt_off00010588.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10588 10872 bytes
SHA-256: 90ddaf8a40bcff210fccfa78af2cc8f5275c70e6b61bd7c1186cd85bb9cf5674

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