Drachtio-server: Off-by-one Error
CVE-2022-47517 is a high-severity off-by-one error vulnerability in Drachtio-server from Drachtio, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 0.8.19 as the first without the flaw, so updating Drachtio-server to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 1.56% chance of exploitation within 30 days, higher than 76% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Drachtio-server to 0.8.19 or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Drachtio | Drachtio-server | before 0.8.19 | 0.8.19 |
Version data comes from NVD's product matching. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.5 | High | NVD |
| CVSS 3.1 | 7.5 | High | CISA (ADP) |
Official description
An issue was discovered in the libsofia-sip fork in drachtio-server before 0.8.19. It allows remote attackers to cause a denial of service (daemon crash) via a crafted UDP message that causes a url_canonize2 heap-based buffer over-read because of an off-by-one error.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Off-by-one Error
A product calculates or uses an incorrect maximum or minimum value that is 1 more, or 1 less, than the correct value.
How developers prevent this class of flaw
- When copying character arrays or using character manipulation methods, the correct size parameter must be used to account for the null terminator that needs to be added at the end of the array. Some examples of functions susceptible to this weakness in C include strcpy(), strncpy(), strcat(), strncat(), printf(), sprintf(), scanf() and sscanf().
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- github.com/davehorton/sofia-sip/commit/22c1bd191f0acbf11f0c0fbea1845d9bf9dcd47eThird Party Advisory
- github.com/davehorton/sofia-sip/commit/bfc79d85c8f3a4798a3305fb98f5a11c11d0d29fThird Party Advisory
Technical write-ups (may include proof of concept)
- github.com/drachtio/drachtio-server/issues/243Exploit, Third Party Advisory
Other vulnerabilities in Drachtio-server
- 7.5 High severity
- 7.5 High severity
Recent Off-by-one Error vulnerabilities
- 7.5 High severity
- 8.6 High severity
- 9.8 Critical severity
- 9.8 Critical severity
- 7.8 High severity
Sudo Heap-Based Buffer Overflow Exploited
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