Malicious PDF — malware analysis report

Static analysis result for SHA-256 f512b8b791ff8cea…

MALICIOUS

PDF

111.5 KB Created: 2021-04-23 23:18:20 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-29
MD5: f199897f755811dd32750038c1a5629e SHA-1: f6671577047bdf2e788efebb1729cd674ec968ed SHA-256: f512b8b791ff8cea3e6d0c7f77bffa9a51b55ed3eabd082d35bc936ddae43333
126 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many pointing to disposable domains, and is flagged by ML classifiers and ClamAV as malicious phishing content. The document body, though heavily obfuscated, suggests a lure related to 'conjecture number theory' to entice users to click on the embedded links. The presence of PDF_SEO_DISPOSABLE_LINK_FARM heuristic indicates a link farm strategy, likely to distribute malicious content or phish for credentials.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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://spotlight-sites.com/sites/default/files/webform/sugugijokasu.pdf In PDF document text
    • https://www.a1touchsolution.nl/sites/default/files/togivem.pdfIn PDF document text
    • http://spotlight-sites.com/sites/default/files/webform/loboje.pdfIn PDF document text
    • http://www.muttypawsacademy.com/sites/default/files/webform/vaccines/taxevoxasubosiwugudabi.pdfIn PDF document text
    • https://grossenbacher.co.nz/en/system/files/avoidance-training-certificates/22559513310.pdfIn PDF document text
    • https://www.enwidth.com/sites/default/files/webform/resumes/fudigebifofonixetizitalu.pdfIn PDF document text
    • https://vectorcorp.net/sites/default/files/webform/resume/dufovomajaxavekasodulep.pdfIn PDF document text
    • https://vectorcorp.net/sites/default/files/webform/resume/86303695333.pdfIn PDF document text
    • https://www.mainephilanthropy.org/sites/default/files/50588642306.pdfIn PDF document text
    • https://www.blplegal.com/sites/default/files/webform/vogelunejubujapezidugave.pdfIn PDF document text
    • http://www.pbttphtk.gov.my/sites/default/files/webform/33269367294.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/9027254294.pdfIn PDF document text
    • https://www.blplegal.com/sites/default/files/webform/58709767715.pdfIn PDF document text
    • https://www.uts.cw/sites/default/files/webform/89737617204.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/1eyvgo/aqOO/~3/S30rS-6n6vg/uplcv?utm_term=conjecture+number+theory+definitionPDF link annotation
    • https://lib.asu.edu/system/files/webform/98562832035.pdfIn PDF document text
    • https://minorsoncampus.princeton.edu/system/files/webform/wetesagepe.pdfIn PDF document text
    • https://minorsoncampus.princeton.edu/system/files/webform/posilo.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
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00015aab.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15AAB 5064 bytes
SHA-256: 3794c8e9d5ffeea0fc5e1ccbd6d898912281307180bad267844011e91566a5dd
font_01_sfnt_off00016bc2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x16BC2 13476 bytes
SHA-256: 02805d82061ceaea8c69736d5fa241efdb8087dd6ead9fe1c205a7896b1c9219
font_02_sfnt_off00019915.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x19915 16688 bytes
SHA-256: 62511001643545ae3bcf9f27df679f56894417795d0caadea6bcf4c8306ff079

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