Malicious PDF — malware analysis report

Static analysis result for SHA-256 7c823327e7feb68d…

MALICIOUS

PDF

77.4 KB Created: 2021-04-18 10:51:18 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-11
MD5: ca83afad0d93a16afae1ff4859b4fba2 SHA-1: b92019d67ca1e509ad64734cf8c41f5ba03e481c SHA-256: 7c823327e7feb68dc7963edff55940543fc506c3debdc3f1f26bb3906a5852eb
126 Risk Score

Malware Insights

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

The PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous embedded URLs, many pointing to suspicious domains, and the document body, though heavily obfuscated, suggests a lure related to a physics textbook. The presence of external URIs and a link farm heuristic further supports the attack pattern of directing users to potentially harmful content.

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 https://www.woonsocketri.org/system/temporary/webform/54194604641.pdf In PDF document text
    • https://ambrose.edu/sites/default/files/webform/9979090083.pdfIn PDF document text
    • http://www.grotekeukens.be/sites/default/files/webform/gmawards2018/87706268510.pdfIn PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/vewamilobofesiwukor.pdfIn PDF document text
    • https://www.mainephilanthropy.org/sites/default/files/30695142459.pdfIn PDF document text
    • http://www.grotekeukens.be/sites/default/files/webform/gmawards2018/dakatiwilu.pdfIn PDF document text
    • https://www.natsihwa.org.au/sites/default/files/webform/xugapovapoz.pdfIn PDF document text
    • http://pilgrimland.com/sites/default/files/webform/resume-uploads/woluweweketasuzizolog.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/59680287402.pdfIn PDF document text
    • https://www.enwidth.com/sites/default/files/webform/resumes/60015669747.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/BkSY9tpko7c/uplcv?utm_term=physics+textbook+giancoliPDF link annotation
    • https://community.princeton.edu/system/files/webform/40347257249.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_off0000f1ef.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF1EF 5340 bytes
SHA-256: f9f9d7e05b4b37a1ed91516002e4c90035c97d14d744bfbd77d9cf8736a5bdd5
font_01_sfnt_off0001042b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1042B 10920 bytes
SHA-256: 235a7e384a4008afc33a23e1f238e2f13885a29f8784d3845ff8800bdc385036

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