5526416 2000-09-28 18:49 /46 rader/ Brevbäraren (som är implementerad i) Python Mottagare: Bugtraq (import) <12981> Ärende: another wu-ftpd exploit ------------------------------------------------------------ From: George Bakos <alpinista@BIGFOOT.COM> To: BUGTRAQ@SECURITYFOCUS.COM Message-ID: <00092801261400.11851@ath.alpinista.phrozen.org> Yesterday www.hack.co.za made available yet another format string stack overwrite exploit for wu-ftpd 2.6.0-*. I have seen an increased level of scanning for port 21 in the past 36 hours, no doubt attributable to this latest SITE EXEC vulnerability. This problem is previously addressed by bugtraq id 1387 and CERT/CC CA-2000-13 http://www.cert.org/advisories/CA-2000-13.html The new tool (wu-lnx.c) in the lab against Mandrake 7.1 and RH 6.0 shows limited success as well as 100% effectiveness against RH 6.2. Version 2.6.1 does not appear vulnerable. A preliminary scrub of the code and traces indicated that user data supplied via the PASS command is stuffed with shellcode and a SITE EXEC then overwrites a stack pointer to call it. The following is an entry left in /var/log/messages on the target box. Note the last line. Sep 28 02:46:25 drteeth ftpd[14989]: ANONYMOUS FTP LOGIN FROM grover.tester.org [192.168.222.1], ? 1À1Û1É°FÍ1À1ÛCÙA°? Íëk^1À1É^^AF^Df¹ÿ^A°'Í1À^^A°=Í1À1Û^^HC^B1ÉþÉ1À^^ H°^LÍþÉuó1ÀF^I^^H°=Íþ^N°0þÈF^D1ÀF^Gv^HF^LóN^H V^L°^KÍ1À1Û°^AÍèÿÿÿ0bin0sh1..11 As the parent service (inetd) is not affected, here may be no external indication that a site has been attacked. Additionally, this is not a buffer overflow, and no process will exit unexpectedly. Ndiff and similar techniques will fail to detect any changes in the status of listening inet ports on exploited systems. This is another incarnation of a very serious vulnerability. If you are running wu-ftpd 2.60-*, it is advised that you upgrade to the 2.6.1 release. George Bakos Systems Security Engineer EWA-IIT alpinista@bigfoot.com (5526416) ------------------------------------------(Ombruten)