Sendmail » Sendmail » 8.11.4 : Security Vulnerabilities, CVEs,

sendmail through 8.17.2 allows SMTP smuggling in certain configurations. Remote attackers can use a published exploitation technique to inject e-mail messages with a spoofed MAIL FROM address, allowing bypass of an SPF protection mechanism. This occurs because sendmail supports <LF>.<CR><LF> but some other popular e-mail servers do not. This is resolved in 8.18 and later versions with 'o' in srv_features.

ALPACA is an application layer protocol content confusion attack, exploiting TLS servers implementing different protocols but using compatible certificates, such as multi-domain or wildcard certificates. A MiTM attacker having access to victim's traffic at the TCP/IP layer can redirect traffic from one subdomain to another, resulting in a valid TLS session. This breaks the authentication of TLS and cross-protocol attacks may be possible where the behavior of one protocol service may compromise the other at the application layer.

The sm_close_on_exec function in conf.c in sendmail before 8.14.9 has arguments in the wrong order, and consequently skips setting expected FD_CLOEXEC flags, which allows local users to access unintended high-numbered file descriptors via a custom mail-delivery program.

sendmail before 8.14.4 does not properly handle a '\0' character in a Common Name (CN) field of an X.509 certificate, which (1) allows man-in-the-middle attackers to spoof arbitrary SSL-based SMTP servers via a crafted server certificate issued by a legitimate Certification Authority, and (2) allows remote attackers to bypass intended access restrictions via a crafted client certificate issued by a legitimate Certification Authority, a related issue to CVE-2009-2408.

Heap-based buffer overflow in Sendmail before 8.13.2 allows remote attackers to cause a denial of service (daemon crash) and possibly execute arbitrary code via a long X- header, as demonstrated by an X-Testing header.

Use-after-free vulnerability in Sendmail before 8.13.8 allows remote attackers to cause a denial of service (crash) via a long "header line", which causes a previously freed variable to be referenced. NOTE: the original developer has disputed the severity of this issue, saying "The only denial of service that is possible here is to fill up the disk with core dumps if the OS actually generates different core dumps (which is unlikely)... the bug is in the shutdown code (finis()) which leads directly to exit(3), i.e., the process would terminate anyway, no mail delivery or receiption is affected."

Sendmail before 8.13.7 allows remote attackers to cause a denial of service via deeply nested, malformed multipart MIME messages that exhaust the stack during the recursive mime8to7 function for performing 8-bit to 7-bit conversion, which prevents Sendmail from delivering queued messages and might lead to disk consumption by core dump files.

The ClamAV Mail fILTER (clamav-milter) 0.84 through 0.85d, when used in Sendmail using long timeouts, allows remote attackers to cause a denial of service by keeping an open connection, which prevents ClamAV from reloading.

The prescan function in Sendmail 8.12.9 allows remote attackers to execute arbitrary code via buffer overflow attacks, as demonstrated using the parseaddr function in parseaddr.c.

A "potential buffer overflow in ruleset parsing" for Sendmail 8.12.9, when using the nonstandard rulesets (1) recipient (2), final, or (3) mailer-specific envelope recipients, has unknown consequences.

The prescan() function in the address parser (parseaddr.c) in Sendmail before 8.12.9 does not properly handle certain conversions from char and int types, which can cause a length check to be disabled when Sendmail misinterprets an input value as a special "NOCHAR" control value, allowing attackers to cause a denial of service and possibly execute arbitrary code via a buffer overflow attack using messages, a different vulnerability than CVE-2002-1337.

Sendmail 8.9.0 through 8.12.6 allows remote attackers to bypass relaying restrictions enforced by the 'check_relay' function by spoofing a blank DNS hostname.

Sendmail 8.9.0 through 8.12.3 allows local users to cause a denial of service by obtaining an exclusive lock on the (1) alias, (2) map, (3) statistics, and (4) pid files.

Buffer overflow in Sendmail 5.79 to 8.12.7 allows remote attackers to execute arbitrary code via certain formatted address fields, related to sender and recipient header comments as processed by the crackaddr function of headers.c.

Sendmail before 8.12.1, without the RestrictQueueRun option enabled, allows local users to obtain potentially sensitive information about the mail queue by setting debugging flags to enable debug mode.

Sendmail before 8.12.1, without the RestrictQueueRun option enabled, allows local users to cause a denial of service (data loss) by (1) setting a high initial message hop count option (-h), which causes Sendmail to drop queue entries, (2) via the -qR option, or (3) via the -qS option.

Sendmail before 8.12.1 does not properly drop privileges when the -C option is used to load custom configuration files, which allows local users to gain privileges via malformed arguments in the configuration file whose names contain characters with the high bit set, such as (1) macro names that are one character long, (2) a variable setting which is processed by the setoption function, or (3) a Modifiers setting which is processed by the getmodifiers function.

Sendmail 8.10.0 through 8.11.5, and 8.12.0 beta, allows local users to modify process memory and possibly gain privileges via a large value in the 'category' part of debugger (-d) command line arguments, which is interpreted as a negative number.