Local privilege escalation using log file
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: no
- Technical impact: total
Summary
The Netskope client service (prior to R96) on Windows runs as NT AUTHORITY\SYSTEM which writes log files to a writable directory (C:\Users\Public\netSkope) for a standard user. The files are created and written with a SYSTEM account except one file (logplaceholder) which inherits permission giving all users full access control list. Netskope client restricts access to this file by allowing only read permissions as a standard user. Whenever the Netskope client service restarts, it deletes the logplaceholder and recreates, creating a race condition, which can be exploited by a malicious local user to create the file and set ACL permissions on the file. Once the file is created by a malicious user with proper ACL permissions, all files within C:\Users\Public\netSkope\ becomes modifiable by the unprivileged user. By using Windows pseudo-symlink, these files can be pointed to other places in the system and thus malicious users will be able to elevate privileges.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: total
- Record last updated
Affected versions
- Netskope Netskope Client
Version range not reported