There's an off-by-one heap-overflow in the ieee802.11 printer, which can be triggered by a maliciously crafted 802.11 frame. The link type must have been explicitly specified for this to work. The function parse_elements() in print-802_11.c checks the length pbody->tim.length from the frame for too small values in line 265, but then uses the wrong variable in the following range check in line 267. Since pbody->tim.length is defined as a u_int8_t it can hold a maximum value of 255, which in turn would copy 252 bytes into pbody->tim.bitmap, which is only 251 bytes of size. 253 case E_TIM: 254 /* Present, possibly truncated */ 255 pbody->tim_status = TRUNCATED; 256 if (!TTEST2(*(p + offset), 2)) 257 return; 258 memcpy(&pbody->tim, p + offset, 2); 259 offset += 2; 260 if (!TTEST2(*(p + offset), 3)) 261 return; 262 memcpy(&pbody->tim.count, p + offset, 3); 263 offset += 3; 264 265 if (pbody->tim.length <= 3) 266 break; 267 if (pbody->rates.length > sizeof pbody->tim.bitmap) 268 return; 269 if (!TTEST2(*(p + offset), pbody->tim.length - 3)) 270 return; 271 memcpy(pbody->tim.bitmap, p + (pbody->tim.length - 3), 272 (pbody->tim.length - 3)) The current tcpdump release 3.9.5 is still vulnerable. This got fixed [1] in CVS Head and in the tcpdump_3_9 branch. [1] http://cvs.tcpdump.org/cgi-bin/cvsweb/tcpdump/print-802_11.c?r1=1.42&r2=1.43 Best, Moritz Jodeit _______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.grok.org.uk/full-disclosure-charter.html Hosted and sponsored by Secunia - http://secunia.com/