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Binary Variable Learner and Apache exploits

Binary Variable Learner and Apache exploits. Sung Kim MIT. Apache Exploits. http://localhost/re/ldap://local/dn?attributes?scope?filter?extenslsions. http://localhost/re/ldap://local/dn?attributes?scope?filter?extenslsions ?ext. Apache Exploits.

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Binary Variable Learner and Apache exploits

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  1. Binary Variable Learner and Apache exploits Sung Kim MIT

  2. Apache Exploits http://localhost/re/ldap://local/dn?attributes?scope?filter?extenslsions http://localhost/re/ldap://local/dn?attributes?scope?filter?extenslsions?ext

  3. Apache Exploits http://.../ldap://local/dn?attributes?scope?filter?extenslsions?ext Apache 2.0.58 or earlier static char * escape_absolute_uri(char *, unsigned int) { … if (!strncasecmp(uri, "ldap", 4)) { int c = 0; char *token[5]; token[0] = cp = apr_pstrdup(p, cp); while (*cp && c < 5) { if (*cp == '?') { token[++c] = cp + 1; *cp = '\0'; } ++cp; }

  4. Apache Exploits if (!strncasecmp(uri, "ldap", 4)) { int c = 0; char *token[5]; token[0] = cp = apr_pstrdup(p, cp); while (*cp && c < 5) { if (*cp == '?') { token[++c] = cp + 1; *cp = '\0'; } ++cp; }

  5. Apache Exploits if (!strncasecmp(uri, "ldap", 4)) { int c = 0; char *token[5]; token[0] = cp = apr_pstrdup(p, cp); while (*cp && c < 5) { if (*cp == '?') { token[++c] = cp + 1; *cp = '\0'; } ++cp; } token[5] = cp + 1;

  6. Binary Variable if (!strncasecmp(uri, "ldap", 4)) { int c = 0; char *token[5]; token[0] = cp = apr_pstrdup(p, cp); while (*cp && c < 5) { if (*cp == '?') { token[++c] = cp + 1; *cp = '\0'; } ++cp; } loop: jge     end_loop mov     ecx,dword ptr [ebp-18h] mov    dword ptr [ebp+ecx*4-14h], eax jmp     loopend_loop:  push    offset buf_over! (00409a38)

  7. Binary Variable loop: jgeend_loop movecx,dwordptr [ebp-18h]movdwordptr [ebp+ecx*4-14h], eaxjmp     loopend_loop:  push    offset buf_over! (00409a38) token[++c] = cp + 1;

  8. Binary Variable loop: jgeend_loop movecx,dwordptr [ebp-18h]movdwordptr [ebp+ecx*4-14h], eaxjmp     loopend_loop:  push    offset buf_over! (00409a38) token[++c] = cp + 1; movdwordptr [ebp+ecx*4-14h], eax

  9. Binary Variable movdwordptr [ebp+ecx*4-14h], eax Base Offset Source Index

  10. Binary Variable push 14h ; variable name push ebp; variable name push ecx; variable value call write_binary_variable movdwordptr [ebp+ecx*4-14h], eax

  11. Community Learning User User User …… Apache Apache Apache Invariants Invariants Invariants CMS ..escape_absolute_uri(char *, unsigned int):::ENTER_4010A5binary_var <= 4 binary_var>= 1

  12. Patch (Manual) !(ecx <= 4) then jmp skip movdwordptr [ebp+ecx*4-14h], eax skip:

  13. Conclusions • Implemented preliminary binary variable learning (BVL) • Generated valid invariants • Applied BVL to Apache and its exploits • Showed the(manual) patch can prevent the exploit

  14. Binary Variable Learner and Apache exploits Sung Kim MIT

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