Impact

The Keylime registrar does not enforce mutual TLS (mTLS) client certificate authentication since version 7.12.0. The registrar's TLS context is configured with ssl.CERTOPTIONAL instead of ssl.CERTREQUIRED, allowing any client to connect to protected API endpoints without presenting a valid client certificate.

Who is impacted: - All Keylime deployments running versions 7.12.0 through 7.13.0 - Environments where the registrar HTTPS port (default 8891) is network-accessible to untrusted clients

What an attacker can do: - List all registered agents (GET /v2/agents/) - enumerate the entire agent inventory - Retrieve agent details (GET /v2/agents/{uuid}) - obtain public TPM keys, certificates, and network locations (IP/port) of any agent - Delete any agent (DELETE /v2/agents/{uuid}) - remove agents from the registry, disrupting attestation services

Note: The exposed TPM data (EK, AK, certificates) consists of public keys and certificates. Private keys remain protected within TPM hardware. The HMAC secret used for challenge-response validation is stored in the database but is not exposed via the API.

Affected versions: >= 7.12.0, <= 7.13.0

Fixed versions: 7.12.2, >= 7.13.1

Patches

A patch for the affected released versions is available. It removes the line that override the configuration of ssl.verifymode, leaving the CERTREQUIRED value set by webutil.initmtls():

diff diff --git a/keylime/web/base/server.py b/keylime/web/base/server.py index 1d9a9c2..859b23a 100644 --- a/keylime/web/base/server.py +++ b/keylime/web/base/server.py @@ -2,7 +2,6 @@ import asyncio import multiprocessing from abc import ABC, abstractmethod from functools import wraps -from ssl import CERTOPTIONAL from typing import TYPECHECKING, Any, Callable, Optional

import tornado @@ -252,7 +251,6 @@ class Server(ABC): self.httpsport = config.getint(component, "tlsport", fallback=0) self.maxuploadsize = config.getint(component, "maxuploadsize", fallback=104857600) self.sslctx = webutil.initmtls(component) - self.sslctx.verifymode = CERTOPTIONAL

def get(self, pattern: str, controller: type["Controller"], action: str, allowinsecure: bool = False) -> None: """Creates a new route to handle incoming GET requests issued for paths which match the given

Users should upgrade to the patched version once it is released.

Workarounds

If upgrading is not immediately possible, apply one of the following mitigations:

1. Network isolation (Recommended)

Restrict access to the registrar HTTPS port (default 8891) using firewall rules to allow only trusted hosts (verifier, tenant):

Example using iptables iptables -A INPUT -p tcp --dport 8891 -s <verifierip> -j ACCEPT iptables -A INPUT -p tcp --dport 8891 -s <tenantip> -j ACCEPT iptables -A INPUT -p tcp --dport 8891 -j DROP

2. Reverse proxy with mTLS enforcement

Deploy a reverse proxy (nginx, HAProxy) in front of the registrar that enforces client certificate authentication:

Example nginx configuration server { listen 8891 ssl; sslcertificate /path/to/server.crt; sslcertificatekey /path/to/server.key; sslclientcertificate /path/to/ca.crt; sslverifyclient on; # Enforce client certificates

location / { proxypass https://localhost:8892; # Internal registrar port } }

A flaw was found in GLib. A state confusion issue exists in gdbusnodeinfonewforxml() in the gio/gdbusintrospection.c file when processing malformed D-Bus introspection XML, specifically with a node element nested within other elements like method, signal, property or arg. This issue can cause an unsigned integer overflow and lead to an out-of-bounds read, resulting in a denial of service.

A flaw was found in the libtiff library. A remote attacker could exploit a signed integer overflow vulnerability in the putcontig8bitYCbCr44tile function by providing a specially crafted TIFF file. This flaw can lead to an out-of-bounds heap write due to incorrect memory pointer calculations, potentially causing a denial of service (application crash) or arbitrary code execution.

crypto: algifaead - Revert to operating out-of-place

Fragnesia is a universal Linux local privilege escalation exploit, discovered by William Bowling with the V12 team. Fragnesia is a member of the Dirty Frag vulnerability class. This is a separate bug in the ESP/XFRM from dirtyfrag which has received its own patch. However, it is in the same surface and the mitigation is the same as for dirtyfrag.

It abuses a logic bug in the Linux XFRM ESP-in-TCP subsystem to achieve arbitrary byte writes into the kernel page cache of read-only files, without requiring any race condition.

The technique extends the page-cache write bug class that includes Dirty Pipe: when a TCP socket transitions to espintcp ULP mode after data has already been spliced from a file into the receive queue, the kernel processes the queued file pages as ESP ciphertext. The AES-GCM keystream byte at counter block position 2, byte 0 is XORed directly into the cached file page. By selecting the IV nonce to produce a desired keystream byte, any target byte in the file can be set to any value — one byte per trigger invocation.

The exploit builds a 256-entry lookup table mapping each possible keystream byte to its corresponding nonce, then iterates over a payload, firing the splice/ULP race for each byte that needs changing. It writes a small position-independent ELF stub (setresuid/setresgid/execve /bin/sh) over the first 192 bytes of /usr/bin/su in the page cache, then calls execve("/usr/bin/su") to obtain a root shell. The page cache modification is not backed to disk; the on-disk binary is untouched.

A segment fault (SEGV) flaw was found in libtiff that could be triggered by passing a crafted tiff file to the TIFFReadRGBATileExt() API. This flaw allows a remote attacker to cause a heap-buffer overflow, leading to a denial of service.

A flaw was found in libxml2's xmlBuildQName function, where integer overflows in buffer size calculations can lead to a stack-based buffer overflow. This issue can result in memory corruption or a denial of service when processing crafted input.

A flaw in Node.js HTTP request handling causes an uncaught TypeError when a request is received with a header named proto and the application accesses req.headersDistinct.

When this occurs, dest["proto"] resolves to Object.prototype rather than undefined, causing .push() to be called on a non-array. This exception is thrown synchronously inside a property getter and cannot be intercepted by error event listeners, meaning it cannot be handled without wrapping every req.headersDistinct access in a try/catch.

This vulnerability affects all Node.js HTTP servers on 20.x, 22.x, 24.x, and v25.x

A flaw was found in the gdk-pixbuf library. This heap-based buffer overflow vulnerability occurs in the JPEG image loader due to improper validation of color component counts when processing a specially crafted JPEG image. A remote attacker can exploit this flaw without user interaction, for example, via thumbnail generation. Successful exploitation leads to application crashes and denial of service (DoS) conditions.

A vulnerability identified in NetIQ Advance Authentication that leaks sensitive server information. This issue affects NetIQ Advance Authentication version before 6.3.5.1

A flaw was found in libsoup. The package is vulnerable to a heap buffer over-read when sniffing content via the skipinsightwhitespace() function. Libsoup clients may read one byte out-of-bounds in response to a crafted HTTP response by an HTTP server.

jq is a command-line JSON processor. In commits before 2f09060afab23fe9390cce7cb860b10416e1bf5f, the jvparsesized() API in libjq accepts a counted buffer with an explicit length parameter, but its error-handling path formats the input buffer using %s in jvstringfmt(), which reads until a NUL terminator is found rather than respecting the caller-supplied length. This means that when malformed JSON is passed in a non-NUL-terminated buffer, the error construction logic performs an out-of-bounds read past the end of the buffer. The vulnerability is reachable by any libjq consumer calling jvparsesized() with untrusted input, and depending on memory layout, can result in memory disclosure or process termination. The issue has been patched in commit 2f09060afab23fe9390cce7cb860b10416e1bf5f.