######################################################### arc insecure temporary file creation Vendor: http://arc.sourceforge.net/ Advisory: http://www.zataz.net/adviso/arc-09052005.txt Vendor informed: yes Exploit available: yes Impact : low Exploitation : low ######################################################### The vulnerability is caused due to temporary file being created insecurely. The temporary file used for archive creation could be read by untrusted users. Secunia has reported that D1g1t4lLeech has discovered this bug the 2005-09-16. ZATAZ Audit has discovered this bug the 2005-09-05 D1g1t4lLeech you are a true Leecher ;) ########## Versions: ########## arc <= 5.21j ########## Solution: ########## No solutions ######### Timeline: ######### Discovered : 2005-09-05 Vendor notified : no time to report (Leech powa) Vendor response : no reponse Vendor fix : no patch Vendor Sec report (vendor-sec (at) lst (dot) de [email concealed]) : Disclosure : 2005-09-19 ##################### Technical details : ##################### Vulnerable code : ----------------- In arc.c : 210 /* see where temp files go */ 211 #if !_MTS 212 arctemp = calloc(1, STRLEN); 213 if (!(arctemp2 = envfind("ARCTEMP"))) 214 arctemp2 = envfind("TMPDIR"); 215 if (arctemp2) { 216 strcpy(arctemp, arctemp2); 217 n = strlen(arctemp); 218 if (arctemp[n - 1] != CUTOFF) 219 arctemp[n] = CUTOFF; 220 } 221 #if UNIX 222 else strcpy(arctemp, "/tmp/"); 223 #endif 224 #if !MSDOS 225 { 226 static char tempname[] = "AXXXXXX"; 227 strcat(arctemp, mktemp(tempname)); 228 } 229 #else 230 strcat(arctemp, "$ARCTEMP"); 231 #endif 232 #else 233 guinfo("SHFSEP ", gotinf); 234 sepchr[0] = gotinf[0]; 235 guinfo("SCRFCHAR", gotinf); 236 tmpchr[0] = gotinf[0]; 237 arctemp = "-$$$"; 238 arctemp[0] = tmpchr[0]; 239 #endif 240 arctemp2 = NULL; 241 242 #if !UNIX 243 /* avoid any case problems with arguments */ 244 245 for (n = 1; n < num; n++) /* for each argument */ 246 upper(arg[n]); /* convert it to uppercase */ 247 #else 248 /* avoid case problems with command options */ 249 upper(arg[1]); /* convert to uppercase */ 250 #endif 251 252 /* create archive names, supplying defaults */ 253 #if UNIX 254 if (!stat(arg[2],&sbuf)) { 255 if ((sbuf.st_mode & S_IFMT) == S_IFDIR) 256 makefnam(arg[2],".arc",arcname); 257 else 258 strcpy(arcname,arg[2]); 259 } else 260 makefnam(arg[2],".arc",arcname); 261 #else 262 makefnam(arg[2], ".ARC", arcname); 263 #endif Take a look on a the right off temporary files in /tmp : -rw-r--r-- 1 root root 1564 Sep 5 10:28 A3C6Zs4.arc The file should not be world readable. The same problem for marc.c ######### Related : ######### Bug report : CVE : ##################### Credits : ##################### Eric Romang (eromang (at) zataz (dot) net [email concealed] - ZATAZ Audit) Thxs to Gentoo Security Team. (Taviso, jaervosz, solar, Koon, etc.)