In Irssi before 1.0.5, overlong nicks or targets may result in a NULL pointer dereference while splitting the message.

Multiple vulnerabilities have been discovered in Irssi, a terminal based IRC client. The Common Vulnerabilities and Exposures project identifies the following problems :

  - CVE-2017-10965     Brian 'geeknik' Carpenter of Geeknik Labs discovered     that Irssi does not properly handle receiving messages     with invalid time stamps. A malicious IRC server can     take advantage of this flaw to cause Irssi to crash,     resulting in a denial of service.

  - CVE-2017-10966     Brian 'geeknik' Carpenter of Geeknik Labs discovered     that Irssi is susceptible to a use-after-free flaw     triggered while updating the internal nick list. A     malicious IRC server can take advantage of this flaw to     cause Irssi to crash, resulting in a denial of service.

  - CVE-2017-15227     Joseph Bisch discovered that while waiting for the     channel synchronisation, Irssi may incorrectly fail to     remove destroyed channels from the query list, resulting     in use after free conditions when updating the state     later on. A malicious IRC server can take advantage of     this flaw to cause Irssi to crash, resulting in a denial     of service.

  - CVE-2017-15228     Hanno Boeck reported that Irssi does not properly handle     installing themes with unterminated colour formatting     sequences, leading to a denial of service if a user is     tricked into installing a specially crafted theme.

  - CVE-2017-15721     Joseph Bisch discovered that Irssi does not properly     handle incorrectly formatted DCC CTCP messages. A remote     attacker can take advantage of this flaw to cause Irssi     to crash, resulting in a denial of service.

  - CVE-2017-15722     Joseph Bisch discovered that Irssi does not properly     verify Safe channel IDs. A malicious IRC server can take     advantage of this flaw to cause Irssi to crash,     resulting in a denial of service.

  - CVE-2017-15723     Joseph Bisch reported that Irssi does not properly     handle overlong nicks or targets resulting in a NULL     pointer dereference when splitting the message and     leading to a denial of service.

The remote Ubuntu 14.04 LTS / 16.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-3465-1 advisory.

    Brian Carpenter discovered that Irssi incorrectly handled messages with invalid time stamps. A malicious     IRC server could use this issue to cause Irssi to crash, resulting in a denial of service.
    (CVE-2017-10965)

    Brian Carpenter discovered that Irssi incorrectly handled the internal nick list. A malicious IRC server     could use this issue to cause Irssi to crash, resulting in a denial of service. (CVE-2017-10966)

    Joseph Bisch discovered that Irssi incorrectly removed destroyed channels from the query list. A malicious     IRC server could use this issue to cause Irssi to crash, resulting in a denial of service.
    (CVE-2017-15227)

    Hanno Bck discovered that Irssi incorrectly handled themes. If a user were tricked into using a     malicious theme, a attacker could use this issue to cause Irssi to crash, resulting in a denial of     service. (CVE-2017-15228)

    Joseph Bisch discovered that Irssi incorrectly handled certain DCC CTCP messages. A malicious IRC server     could use this issue to cause Irssi to crash, resulting in a denial of service. (CVE-2017-15721)

    Joseph Bisch discovered that Irssi incorrectly handled certain channel IDs. A malicious IRC server could     use this issue to cause Irssi to crash, resulting in a denial of service. (CVE-2017-15722)

    Joseph Bisch discovered that Irssi incorrectly handled certain long nicks or targets. A malicious IRC     server could use this issue to cause Irssi to crash, resulting in a denial of service. (CVE-2017-15723)

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

New irssi packages are available for Slackware 14.0, 14.1, 14.2, and
-current to fix security issues.

This security update for irssi to version 1.0.5 addresses the following security issues :

  - CVE-2017-15228: When installing themes with unterminated     colour formatting sequences, Irssi may access data     beyond the end of the string. This issue could have     resulted in denial of service (remote crash) when     installing a malicious or broken theme file.

  - CVE-2017-15227: While waiting for the channel     synchronisation, Irssi may incorrectly fail to remove     destroyed channels from the query list, resulting in use     after free conditions when updating the state later on.
    This issue could have caused denial of service (remote     crash) when connecting to a malicious or broken ircd.

  - CVE-2017-15721: Certain incorrectly formatted DCC CTCP     messages could cause NULL pointer dereference. This     issue could have caused denial of service (remote crash)     when connecting to a malicious or broken ircd.

  - CVE-2017-15723: Overlong nicks or targets may result in     a NULL pointer dereference while splitting the message.
    This issue could have caused denial of service (remote     crash) when connecting to a malicious or broken ircd.

  - CVE-2017-15722: In certain cases Irssi may fail to     verify that a Safe channel ID is long enough, causing     reads beyond the end of the string.

Irssi reports :

When installing themes with unterminated colour formatting sequences, Irssi may access data beyond the end of the string.

While waiting for the channel synchronisation, Irssi may incorrectly fail to remove destroyed channels from the query list, resulting in use after free conditions when updating the state later on.

Certain incorrectly formatted DCC CTCP messages could cause NULL pointer dereference.

Overlong nicks or targets may result in a NULL pointer dereference while splitting the message.

In certain cases Irssi may fail to verify that a Safe channel ID is long enough, causing reads beyond the end of the string.

ID	Name	Product	Family	Severity
104400	Debian DSA-4016-1 : irssi - security update	Nessus	Debian Local Security Checks	critical
104212	Ubuntu 14.04 LTS / 16.04 LTS : Irssi vulnerabilities (USN-3465-1)	Nessus	Ubuntu Local Security Checks	critical
104146	Slackware 14.0 / 14.1 / 14.2 / current : irssi (SSA:2017-298-01)	Nessus	Slackware Local Security Checks	high
104114	openSUSE Security Update : irssi (openSUSE-2017-1189)	Nessus	SuSE Local Security Checks	high
104062	FreeBSD : irssi -- multiple vulnerabilities (85e2c7eb-b74b-11e7-8546-5cf3fcfdd1f1)	Nessus	FreeBSD Local Security Checks	high

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CVE-2017-15723

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