The (1) publickey_make_dss, (2) publickey_make_rsa, (3) signature_from_string, (4) ssh_do_sign, and (5) ssh_sign_session_id functions in keys.c in libssh before 0.5.3 free "an invalid pointer on an error path," which might allow remote attackers to cause a denial of service (crash) via unspecified vectors.

This update of libssh fixed various memory management issues that could have security implications (Code execution, Denial of Service).

The remote host is affected by the vulnerability described in GLSA-201402-26 (libssh: Arbitrary code execution)

    Multiple buffer overflow, double free, and integer overflow       vulnerabilities have been discovered in libssh.
  Impact :

    A remote attacker could possibly execute arbitrary code with the       privileges of the process or cause a Denial of Service condition.
  Workaround :

    There is no known workaround at this time.

Updated libssh packages fix security vulnerabilities :

Multiple double free flaws, buffer overflow flaws, invalid free flaws, and improper overflow checks in libssh before 0.5.3 could enable a denial of service attack against libssh clients, or possibly arbitrary code execution (CVE-2012-4559, CVE-2012-4560, CVE-2012-4561 and CVE-2012-4562).

Yong Chuan Koh discovered that libssh incorrectly handled certain negotiation requests. A remote attacker could use this to cause libssh to crash, resulting in a denial of service (CVE-2013-0176).

This is an important SECURITY and maintenance release in order to address CVE-2012-4559, CVE-2012-4560, CVE-2012-4561 and CVE-2012-4562.

Note that Tenable Network Security has extracted the preceding description block directly from the Fedora security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

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

Multiple vulnerabilities were discovered in libssh by Florian Weimer and Xi Wang :

  - CVE-2012-4559: multiple double free() flaws
  - CVE-2012-4561: multiple invalid free() flaws
  - CVE-2012-4562: multiple improper overflow checks

Those could lead to a denial of service by making an SSH client linked to libssh crash, and maybe even arbitrary code execution.

Multiple double free(), buffer overflow, invalid free() and improper overflow checks vulnerabilities was found and corrected in libssh (CVE-2012-4559, CVE-2012-4560, CVE-2012-4561, CVE-2012-4562).

The updated packages have been upgraded to the 0.5.3 version which is not affected by these issues.

Xi Wang and Florian Weimer discovered that libssh incorrectly handled memory. A remote attacker could use this to cause libssh to crash, resulting in a denial of service, or possibly execute arbitrary code.
(CVE-2012-4559, CVE-2012-4560, CVE-2012-4561, CVE-2012-4562).

Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

ID	Name	Product	Family	Severity
74834	openSUSE Security Update : libssh (openSUSE-SU-2012:1620-1)	Nessus	SuSE Local Security Checks	high
74829	openSUSE Security Update : libssh (openSUSE-SU-2012:1622-1)	Nessus	SuSE Local Security Checks	high
72640	GLSA-201402-26 : libssh: Arbitrary code execution	Nessus	Gentoo Local Security Checks	high
66059	Mandriva Linux Security Advisory : libssh (MDVSA-2013:045)	Nessus	Mandriva Local Security Checks	high
63173	Fedora 16 : libssh-0.5.3-1.fc16 (2012-18687)	Nessus	Fedora Local Security Checks	high
63168	Slackware 14.0 / current : libssh (SSA:2012-341-02)	Nessus	Slackware Local Security Checks	high
63125	Debian DSA-2577-1 : libssh - several vulnerabilities	Nessus	Debian Local Security Checks	high
63104	Mandriva Linux Security Advisory : libssh (MDVSA-2012:175)	Nessus	Mandriva Local Security Checks	high
63089	Fedora 17 : libssh-0.5.3-1.fc17 (2012-18677)	Nessus	Fedora Local Security Checks	high
63058	Ubuntu 10.04 LTS / 11.10 / 12.04 LTS / 12.10 : libssh vulnerabilities (USN-1640-1)	Nessus	Ubuntu Local Security Checks	high
63054	Fedora 18 : libssh-0.5.3-1.fc18 (2012-18610)	Nessus	Fedora Local Security Checks	high

Detections

Analytics

CVE-2012-4561

high

Tenable Plugins

high

high

high

high

high

high

high

high

high

high

high