The x509parse_crt function in x509.h in PolarSSL 1.1.x before 1.1.7 and 1.2.x before 1.2.8 does not properly parse certificate messages during the SSL/TLS handshake, which allows remote attackers to cause a denial of service (infinite loop and CPU consumption) via a certificate message that contains a PEM encoded certificate.

Multiple security issues have been discovered in PolarSSL, a lightweight crypto and SSL/TLS library :

  - CVE-2013-4623     Jack Lloyd discovered a denial of service vulnerability     in the parsing of PEM-encoded certificates.

  - CVE-2013-5914     Paul Brodeur and TrustInSoft discovered a buffer     overflow in the ssl_read_record() function, allowing the     potential execution of arbitrary code.

  - CVE-2013-5915     Cyril Arnaud and Pierre-Alain Fouque discovered timing     attacks against the RSA implementation.

The remote host is affected by the vulnerability described in GLSA-201310-10 (PolarSSL: Multiple vulnerabilities)

    Multiple vulnerabilities have been discovered in PolarSSL. Please review       the CVE identifiers referenced below for details.
  Impact :

    A remote attacker might be able to cause Denial of Service, conduct a       man-in-the middle attack, compromise an encrypted communication channel,       or obtain sensitive information.
  Workaround :

    There is no known workaround at this time.

PolarSSL 1.2.8

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.

Paul Bakker reports :

A bug in the logic of the parsing of PEM encoded certificates in x509parse_crt() can result in an infinite loop, thus hogging processing power.

While parsing a Certificate message during the SSL/TLS handshake, PolarSSL extracts the presented certificates and sends them on to be parsed. As the RFC specifies that the certificates in the Certificate message are always X.509 certificates in DER format, bugs in the decoding of PEM certificates should normally not be triggerable via the SSL/TLS handshake.

Versions of PolarSSL prior to 1.1.7 in the 1.1 branch and prior to 1.2.8 in the 1.2 branch call the generic x509parse_crt() function for parsing during the handshake. x509parse_crt() is a generic functions that wraps parsing of both PEM-encoded and DER-formatted certificates.
As a result it is possible to craft a Certificate message that includes a PEM encoded certificate in the Certificate message that triggers the infinite loop.

ID	Name	Product	Family	Severity
70533	Debian DSA-2782-1 : polarssl - several vulnerabilities	Nessus	Debian Local Security Checks	medium
70486	GLSA-201310-10 : PolarSSL: Multiple vulnerabilities	Nessus	Gentoo Local Security Checks	high
70054	Fedora 20 : polarssl-1.2.8-1.fc20 (2013-16258)	Nessus	Fedora Local Security Checks	medium
70032	Fedora 18 : polarssl-1.2.8-1.fc18 (2013-16356)	Nessus	Fedora Local Security Checks	medium
70031	Fedora 19 : polarssl-1.2.8-1.fc19 (2013-16317)	Nessus	Fedora Local Security Checks	medium
69337	FreeBSD : polarssl -- denial of service vulnerability (72bf9e21-03df-11e3-bd8d-080027ef73ec)	Nessus	FreeBSD Local Security Checks	medium

Detections

Analytics

CVE-2013-4623

high

Tenable Plugins

medium

high

medium

medium

medium

medium