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Fragnesia Made Public as Latest Linux Local Privilege Escalation Vulnerability

phoronix.com

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Re: Fragnesia Made Public as Latest Linux Local Privilege Escalation Vulnerability

#3
post #2

Lots of privilege escalations these days. But are there that many multiuser Linux systems nowadays ? I'm under the impression the whole landscape is either servers or single-user desktops (and ofc Android phones).

The idea is that you can exploit a service hosted on Linux to run these.

Re: Fragnesia Made Public as Latest Linux Local Privilege Escalation Vulnerability

#5
post #2

Lots of privilege escalations these days. But are there that many multiuser Linux systems nowadays ? I'm under the impression the whole landscape is either servers or single-user desktops (and ofc Android phones).

I impersonate multiple users on my machine for organizational reasons.

LPEs also potentially make user-level malware into system-level malware, which is only marginally more impactful for a single person on a desktop, but considerably harder to clean up. (It also broadens the range of what such malware could exfiltrate from me.)

Re: Fragnesia Made Public as Latest Linux Local Privilege Escalation Vulnerability

#7

Sounds like this one is in the same kernel modules as dirtyfrag, so the existing mitigations (if in place) are sufficient.

RedHat's mitigation is this:

  $ cat /etc/modprobe.d/dirtyfrag.conf
  install esp4 /bin/false
  install esp6 /bin/false
  install rxrpc /bin/false
Are those correct for this exploit?

https://access.redhat.com/security/vulnerabilities/RHSB-2026...

Re: Fragnesia Made Public as Latest Linux Local Privilege Escalation Vulnerability

#9
post #7

Sounds like this one is in the same kernel modules as dirtyfrag, so the existing mitigations (if in place) are sufficient.

RedHat's mitigation is this: $ cat /etc/modprobe.d/dirtyfrag.conf install esp4 /bin/false install esp6 /bin/false install rxrpc /bin/false Are those correct for this exploit? https://access.redhat.com/security/vulnerabilities/RHSB-2026...

I don't know, but the problem with blocking esp4 and esp6 is that IPsec stops working, as I understand it.

Re: Fragnesia Made Public as Latest Linux Local Privilege Escalation Vulnerability

#10
post #7

Sounds like this one is in the same kernel modules as dirtyfrag, so the existing mitigations (if in place) are sufficient.

RedHat's mitigation is this: $ cat /etc/modprobe.d/dirtyfrag.conf install esp4 /bin/false install esp6 /bin/false install rxrpc /bin/false Are those correct for this exploit? https://access.redhat.com/security/vulnerabilities/RHSB-2026...

Yep, that's the advice from AWS for the previous set of vulnerabilities:

https://aws.amazon.com/security/security-bulletins/2026-027-...

That one also includes disabling user namespaces. Could be problematic if they're in use.

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