Description
chan_sip.c in the SIP channel driver in Asterisk Open Source 1.4.x before 1.4.41.2, 1.6.2.x before 1.6.2.18.2, and 1.8.x before 1.8.4.4, and Asterisk Business Edition C.3.x before C.3.7.3, disregards the alwaysauthreject option and generates different responses for invalid SIP requests depending on whether the user account exists, which allows remote attackers to enumerate account names via a series of requests.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | asterisk | 1:1.8.4.4~dfsg-1 | — |
| Debian 6.0 | asterisk | 1:1.6.2.9-2+squeeze3 | DSA-2276-2, DSA-2276-1 |
| Debian 5.0 | asterisk | 1:1.4.21.2~dfsg-3+lenny3 | DSA-2276-2, DSA-2276-1 |
Advisories 2
- DSA-2276-2 asterisk - multiple issues Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-2276-1 asterisk - multiple issues Debian Security (DSA / DLA) · Mar 9, 2026