Malicious PDF — malware analysis report

Static analysis result for SHA-256 e6b40809cf0fb2d6…

MALICIOUS

PDF

67.6 KB Created: 2021-04-25 18:56:45 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-23
MD5: bc9af548babe5513578d9c8d692ac7dc SHA-1: 4de5547b9e3488c75e871328b65180859dee1c9a SHA-256: e6b40809cf0fb2d69addd937170a28a5f481b8584a1cb585468f4da91d97fa36
66 Risk Score

Malware Insights

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

The sample is a PDF file flagged by an ML classifier as malicious. It contains numerous embedded URLs, with one heuristic specifically identifying it as a link farm on disposable hosting. The document body is heavily obfuscated, preventing a clear understanding of its direct user-facing content, but the presence of multiple links suggests a redirection or SEO-based attack. No scripts were extracted from this sample.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 4

  • 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://klm3fg.grhosting.cz/sites/default/files/webform/files/78191676466.pdf In PDF document text
    • http://pilgrimland.com/sites/default/files/webform/resume-uploads/61975266633.pdfIn PDF document text
    • http://www.friendlycc.com/sites/default/files/webform/topevonizudurazot.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/28961662769.pdfIn PDF document text
    • https://www.clinicasfantamaria.ro/sites/default/files/webform/33767122539.pdfIn PDF document text
    • http://klm3fg.grhosting.cz/sites/default/files/webform/files/30253637425.pdfIn PDF document text
    • http://www.muttypawsacademy.com/sites/default/files/webform/vaccines/72246142748.pdfIn PDF document text
    • https://www.termis.org/system/files/webform/vomijalikuwukilowerosi.pdfIn PDF document text
    • http://www.grotekeukens.be/sites/default/files/webform/gmawards2018/gurolaxi.pdfIn PDF document text
    • http://pilgrimland.com/sites/default/files/webform/resume-uploads/64296936159.pdfIn PDF document text
    • https://ambrose.edu/sites/default/files/webform/49323480199.pdfIn PDF document text
    • http://spotlight-sites.com/sites/default/files/webform/wokasonexigugeb.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/zMnd8XtcwSM/uplcv?utm_term=six+ideas+that+shaped+physics+solutions+manualPDF link annotation
    • https://www.ice.cam.ac.uk/sites/www.ice.cam.ac.uk/files/webform/tivajojisepizoni.pdfIn PDF document text
    • https://campusrec.princeton.edu/system/files/webform/putiwokareviwe.pdfIn PDF document text
    • https://minorsoncampus.princeton.edu/system/files/webform/kuwidiloj.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_off0000c8fb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC8FB 5492 bytes
SHA-256: ee17b7e00b63dee85d89b7f7a4c54be1cfc103bc1a1d5464a481004882e79240
font_01_sfnt_off0000db94.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDB94 10724 bytes
SHA-256: 81a422bd54ecfc2af0ca51c20a77f4b2368ebcc9f5380fb32d4f11e93566ff32