Malicious PDF — malware analysis report

Static analysis result for SHA-256 11cac9fcf69c958b…

MALICIOUS

PDF

77.6 KB Created: 2021-04-09 06:11:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-29
MD5: 5ee0b5777d96b4a9ec416191c074d350 SHA-1: c6a7835e72f9de12bb763e9b746c4fad4f53d79c SHA-256: 11cac9fcf69c958b8f302f15439b7113a35615871612294703b27647f625ebb0
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The file is a PDF identified as malicious by ML classifiers and ClamAV, specifically flagged as a phishing trojan. Heuristics indicate it functions as a link farm, directing users to potentially malicious PDFs on disposable domains. The document body is heavily obfuscated and contains metadata suggesting it was generated by wkhtmltopdf, which is not typical for legitimate documents.

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://www.woonsocketri.org/system/temporary/webform/51053607868.pdf In PDF document text
    • https://www.a1touchsolution.nl/sites/default/files/dovav.pdfIn PDF document text
    • https://web.liderpapel.com/sites/default/files/webform/36759883892.pdfIn PDF document text
    • http://www.grotekeukens.be/sites/default/files/webform/gmawards2018/jebumimebugamoto.pdfIn PDF document text
    • https://vectorcorp.net/sites/default/files/webform/resume/sowasipaxezok.pdfIn PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/78191676466.pdfIn PDF document text
    • https://www.osgeurope.com/sites/osg-corporate.dev/files/webform/19824824677.pdfIn PDF document text
    • https://www.uts.cw/sites/default/files/webform/tidenopuzi.pdfIn PDF document text
    • https://www.dgs-interparts.be/sites/default/files/viwiredozilopuvotudulufez.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/1eyvgo/aqOO/~3/DOqCt-cVA4I/uplcv?utm_term=cirrhose+alcoolique+pdfPDF link annotation
    • https://www.ice.cam.ac.uk/sites/www.ice.cam.ac.uk/files/webform/ruwitik.pdfIn PDF document text
    • https://ec.europa.eu/eip/agriculture/sites/default/files/webform/9071701793.pdfIn PDF document text
    • https://www.vub.be/sites/vub/files/webform/16824703900.pdfIn PDF document text
    • https://campusrec.princeton.edu/system/files/webform/luzatebinibaxopititum.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e10e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE10E 5088 bytes
SHA-256: 23059ede9de44104d9b039747e5546307738ac80015bea239575beb17be6edb9
font_01_sfnt_off0000f267.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF267 12644 bytes
SHA-256: f019c1be768a59a15a1e39bf709d113f401f7c26688ad59b75f1fb51753d20ee
font_02_sfnt_off00011a4f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11A4F 4324 bytes
SHA-256: a542ec26cea93e049a2e27cd59b1347dd9bbdea13775fd7b822b3c2b3136116f