Malicious PDF — malware analysis report

Static analysis result for SHA-256 bf169b9f266ba48c…

MALICIOUS

PDF

72.3 KB Created: 2021-04-18 17:14:49 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-27
MD5: f07c9e27d5aa533091bf3938b97a0d13 SHA-1: 79d6fe34d80d288c5e02e953341850c2bcf2efb6 SHA-256: bf169b9f266ba48c263519e3d0f8b6d20c176349d48b64d141382ca7f73d2a3b
134 Risk Score

Malware Insights

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

The PDF document was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs, many of which point to disposable domains or are structured as link farms, suggesting an attempt to obscure the true destination. The presence of a 'download' button heuristic further supports a malicious intent to trick the user into downloading a payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 6

  • 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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://cicatsalud.com/html/sites/default/files/webform/25507329945.pdf In PDF document text
    • https://www.blplegal.com/sites/default/files/webform/58709767715.pdfIn PDF document text
    • https://www.ofalloncasting.com/sites/default/files/webform/zuloliresu.pdfIn PDF document text
    • http://www.muttypawsacademy.com/sites/default/files/webform/vaccines/40041164747.pdfIn PDF document text
    • https://www.pharoxglobal.com/sites/default/files/webform/7322176875.pdfIn PDF document text
    • https://www.enwidth.com/sites/default/files/webform/resumes/60015669747.pdfIn PDF document text
    • http://www.friendlycc.com/sites/default/files/webform/zuguxinukebezukul.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/YTWXjIUwRh0/uplcv?utm_term=physicians+desk+reference+2020+onlinePDF link annotation
    • https://community.princeton.edu/system/files/webform/luzixuganigofifabeja.pdfIn PDF document text
    • https://www.healthdata.org/sites/default/files/resumes/fanonexujezurexuli.pdfIn PDF document text
    • https://campusrec.princeton.edu/system/files/webform/xapedejezorim.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_off0000de59.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDE59 5552 bytes
SHA-256: 342eb43d27044de08a651504ee282c079d40d9e4a592788b6f1f4b8b7cb3b876
font_01_sfnt_off0000f13e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF13E 10420 bytes
SHA-256: 03fe5fbff405bccdac0cd0c15314495f94cc73f0c89fc56a0ee69c0c3f060e2f