FreeBSD VuXML: Documenting security issues in FreeBSD and the FreeBSD Ports Collection

PuTTY -- memory corruption in terminal emulator's erase character handling

Affected packages
0.54 <= putty < 0.66


VuXML ID 0cb0afd9-86b8-11e5-bf60-080027ef73ec
Discovery 2015-11-06
Entry 2015-11-09

Ben Harris reports:

Versions of PuTTY and pterm between 0.54 and 0.65 inclusive have a potentially memory-corrupting integer overflow in the handling of the ECH (erase characters) control sequence in the terminal emulator.

To exploit a vulnerability in the terminal emulator, an attacker must be able to insert a carefully crafted escape sequence into the terminal stream. For a PuTTY SSH session, this must be before encryption, so the attacker likely needs access to the server you're connecting to. For instance, an attacker on a multi-user machine that you connect to could trick you into running cat on a file they control containing a malicious escape sequence. (Unix write(1) is not a vector for this, if implemented correctly.)

Only PuTTY, PuTTYtel, and pterm are affected; other PuTTY tools do not include the terminal emulator, so cannot be exploited this way.


CVE Name CVE-2015-5309