K53955014 : Python vulnerabilities CVE-2016-1494, CVE-2016-6536, CVE-2017-17522, CVE-2017-18207, and CVE-2018-1000030

Security Advisory Description

• CVE-2016-1494

The verify function in the RSA package for Python (Python-RSA) before 3.3 allows attackers to spoof signatures with a small public exponent via crafted signature padding, aka a BERserk attack.

• CVE-2016-6536

The /setup URI on AVer Information EH6108H+ devices with firmware X9.03.24.00.07l allows remote attackers to bypass intended page-access restrictions or modify passwords by leveraging knowledge of a handle parameter value.

• CVE-2017-17522

DISPUTED Lib/webbrowser.py in Python through 3.6.3 does not validate strings before launching the program specified by the BROWSER environment variable, which might allow remote attackers to conduct argument-injection attacks via a crafted URL. NOTE: a software maintainer indicates that exploitation is impossible because the code relies on subprocess.Popen and the default shell=False setting.

• CVE-2017-18207

DISPUTED The Wave_read._read_fmt_chunk function in Lib/wave.py in Python through 3.6.4 does not ensure a nonzero channel value, which allows attackers to cause a denial of service (divide-by-zero and exception) via a crafted wav format audio file. NOTE: the vendor disputes this issue because Python applications “need to be prepared to handle a wide variety of exceptions.”

• CVE-2018-1000030

Python 2.7.14 is vulnerable to a Heap-Buffer-Overflow as well as a Heap-Use-After-Free. Python versions prior to 2.7.14 may also be vulnerable and it appears that Python 2.7.17 and prior may also be vulnerable however this has not been confirmed. The vulnerability lies when multiply threads are handling large amounts of data. In both cases there is essentially a race condition that occurs. For the Heap-Buffer-Overflow, Thread 2 is creating the size for a buffer, but Thread1 is already writing to the buffer without knowing how much to write. So when a large amount of data is being processed, it is very easy to cause memory corruption using a Heap-Buffer-Overflow. As for the Use-After-Free, Thread3->Malloc->Thread1->Free’s->Thread2-Re-uses-Free’d Memory. The PSRT has stated that this is not a security vulnerability due to the fact that the attacker must be able to run code, however in some situations, such as function as a service, this vulnerability can potentially be used by an attacker to violate a trust boundary, as such the DWF feels this issue deserves a CVE.

Impact

There is no impact; F5 products are not affected by these vulnerabilities.