CVE-2023-41360 refers to a recently discovered vulnerability in FRRouting FRR, a widely-used routing software suite. This vulnerability, found in FRR's Border Gateway Protocol implementation (bgpd), could potentially be exploited by an attacker to cause unforeseen issues within the routing system. In this post, we will delve into the details of this vulnerability, provide code snippets for better understanding, and discuss potential exploit scenarios.

Background

FRRouting (FRR) is an IP routing protocol suite for Linux and Unix platforms, providing support for a variety of routing protocols like BGP, OSPF, RIP, and more. It is used to manage the routing tables and connections between various networks for organizations worldwide. The recent discovery of the vulnerability in its BGP Daemon (bgpd) can pose a significant threat to FRR users.

Vulnerability Details

The vulnerability, designated as CVE-2023-41360, lies in the bgpd/bgp_packet.c file of FRRouting FRR. This vulnerability allows for an ahead-of-stream situation when reading the initial byte of the ORF (Outbound Route Filter) header. The function responsible for this issue is the "stream_getc" function. The problem occurs when the "stream_getc" function reads an uninitialized byte, potentially influencing the code execution in the subsequent stages.

Here is an example code snippet from bgpd/bgp_packet.c which demonstrates the vulnerability

uint8_t orf_type;
uint8_t orf_len;
struct stream *s;

// Read the ORF Type
if (stream_getc(s, &orf_type) == NULL) {
    // Error handling code here
}

// Read the ORF Length
if (stream_getc(s, &orf_len) == NULL) {
    // Error handling code here
}

// If the ORF Length is greater than the available stream data size
if (orf_len > STREAM_READABLE(s)) {
    // An ahead-of-stream situation occurs
}

The code snippet above shows that if the ORF Length is greater than the readable data size in the stream, an ahead-of-stream situation happens. This vulnerability could potentially be exploited by an attacker who sends a specially crafted BGP update message with incorrect ORF Length values, causing unexpected behavior.

Original References

1. FRRouting FRR GitHub Repository
2. CVE-2023-41360 - NVD Detail
3. FRRouting Documentation

Exploit Scenarios

While there aren't any known public exploits for this vulnerability yet, the potential consequences of an exploit could be severe. A malicious actor could exploit this vulnerability to tamper with the routing table, causing networks to reroute traffic through unauthorized routes, resulting in a potential data breach, Denial of Service (DoS) attacks, or other security risks.

Mitigation Measures

As the issue has been discovered, FRRouting FRR developers are expected to release a patch to address this vulnerability soon. Users are encouraged to keep an eye on the official FRRouting GitHub repository and install the latest updates to their systems as they become available. Additionally, network administrators should monitor BGP traffic for any unusual patterns or spikes in activity that could indicate an attempt to exploit the vulnerability.

Conclusion

CVE-2023-41360 is a critical vulnerability in the FRRouting FRR software suite that may have serious consequences for the systems running on affected networks. As the potential exploit details emerge, users are advised to stay vigilant, apply the necessary patches, and monitor BGP traffic closely to mitigate the risks associated with this vulnerability. By staying informed and acting proactively, organizations can continue to use FRRouting FRR securely and effectively in their networking infrastructure.

Timeline

Published on: 08/29/2023 04:15:16 UTC
Last modified on: 11/15/2023 05:15:09 UTC