CVE-2023-31137 MaraDNS Integer Underflow Vulnerability in DNS Packet Decompression
A remote attacker can cause a Denial of Service in MaraDNS by sending a crafted DNS packet that triggers an integer underflow and abnormal program termination.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-31137?
CVE-2023-31137 is a high-severity vulnerability in Debian Debian Linux, published on 9 May 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
MaraDNS is open-source software that implements the Domain Name System (DNS). In version 3.5.0024 and prior, a remotely exploitable integer underflow vulnerability in the DNS packet decompression function allows an attacker to cause a Denial of Service by triggering an abnormal program termination.
The vulnerability exists in the `decomp_get_rddata` function within the `Decompress.c` file. When handling a DNS packet with an Answer RR of qtype 16 (TXT record) and any qclass, if the `rdlength` is smaller than `rdata`, the result of the line `Decompress.c:886` is a negative number `len = rdlength - total;`. This value is then passed to the `decomp_append_bytes` function without proper validation, causing the program to attempt to allocate a massive chunk of memory that is impossible to allocate. Consequently, the program exits with an error code of 64, causing a Denial of Service.
One proposed fix for this vulnerability is to patch `Decompress.c:887` by breaking `if(len <= 0)`, which has been incorporated in version 3.5.0036 via commit bab062bde40b2ae8a91eecd522e84d8b993bab58.
Weakness: CWE-191
Which versions are affected by CVE-2023-31137?
It affects 3 products.
Products include Debian Debian Linux, Fedoraproject Fedora, Maradns Maradns.
How do I fix CVE-2023-31137?
Apply the vendor's patch.
Is CVE-2023-31137 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-31137 exists.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as DEBIAN-CVE-2023-31137, GHSA-58m7-826v-9c3c, UBUNTU-CVE-2023-31137.