Asterisk Open Source 1.2.x before 1.2.35, 1.4.x before 1.4.26.3, 1.6.0.x before 1.6.0.17, and 1.6.1.x before 1.6.1.9; Business Edition A.x.x, B.x.x before B.2.5.12, C.2.x.x before C.2.4.5, and C.3.x.x before C.3.2.2; AsteriskNOW 1.5; and s800i 1.3.x before 1.3.0.5 generate different error messages depending on whether a SIP username is valid, which allows remote attackers to enumerate valid usernames via multiple crafted REGISTER messages with inconsistent usernames in the URI in the To header and the Digest in the Authorization header.

The SIP channel driver in Asterisk Open Source 1.2.x before 1.2.34, 1.4.x before 1.4.26.1, 1.6.0.x before 1.6.0.12, and 1.6.1.x before 1.6.1.4; Asterisk Business Edition A.x.x, B.x.x before B.2.5.9, C.2.x before C.2.4.1, and C.3.x before C.3.1; and Asterisk Appliance s800i 1.2.x before 1.3.0.3 does not use a maximum width when invoking sscanf style functions, which allows remote attackers to cause a denial of service (stack memory consumption) via SIP packets containing large sequences of ASCII decimal characters, as demonstrated via vectors related to (1) the CSeq value in a SIP header, (2) large Content-Length value, and (3) SDP.

SQL injection vulnerability in the Call Detail Record Postgres logging engine (cdr_pgsql) in Asterisk 1.4.x before 1.4.15, 1.2.x before 1.2.25, B.x before B.2.3.4, and C.x before C.1.0-beta6 allows remote authenticated users to execute arbitrary SQL commands via (1) ANI and (2) DNIS arguments.

SQL injection vulnerability in the Postgres Realtime Engine (res_config_pgsql) in Asterisk 1.4.x before 1.4.15 and C.x before C.1.0-beta6 allows remote attackers to execute arbitrary SQL commands via unknown vectors.

Multiple buffer overflows in the voicemail functionality in Asterisk 1.4.x before 1.4.13, when using IMAP storage, might allow (1) remote attackers to execute arbitrary code via a long combination of Content-type and Content-description headers, or (2) local users to execute arbitrary code via a long combination of astspooldir, voicemail context, and voicemail mailbox fields. NOTE: vector 2 requires write access to Asterisk configuration files.

The IAX2 channel driver (chan_iax2) in Asterisk Open 1.2.x before 1.2.23, 1.4.x before 1.4.9, and Asterisk Appliance Developer Kit before 0.6.0, when configured to allow unauthenticated calls, allows remote attackers to cause a denial of service (resource exhaustion) via a flood of calls that do not complete a 3-way handshake, which causes an ast_channel to be allocated but not released.