The silc_http_server_parse function in lib/silchttp/silchttpserver.c in the internal HTTP server in silcd in Secure Internet Live Conferencing (SILC) Toolkit before 1.1.9 allows remote attackers to overwrite a stack location and possibly execute arbitrary code via a crafted Content-Length header, related to incorrect use of a %lu format string.
The product uses a function that accepts a format string as an argument, but the format string originates from an external source.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Silc_toolkit | Silcnet | * | 1.1.8 (including) |
| Silc_toolkit | Silcnet | 1.1 (including) | 1.1 (including) |
| Silc_toolkit | Silcnet | 1.1.1 (including) | 1.1.1 (including) |
| Silc_toolkit | Silcnet | 1.1.2 (including) | 1.1.2 (including) |
| Silc_toolkit | Silcnet | 1.1.3 (including) | 1.1.3 (including) |
| Silc_toolkit | Silcnet | 1.1.4 (including) | 1.1.4 (including) |
| Silc_toolkit | Silcnet | 1.1.5 (including) | 1.1.5 (including) |
| Silc_toolkit | Silcnet | 1.1.6 (including) | 1.1.6 (including) |
| Silc-toolkit | Ubuntu | dapper | * |
| Silc-toolkit | Ubuntu | hardy | * |
| Silc-toolkit | Ubuntu | intrepid | * |
| Silc-toolkit | Ubuntu | jaunty | * |
| Silc-toolkit | Ubuntu | upstream | * |
When an attacker can modify an externally-controlled format string, this can lead to buffer overflows, denial of service, or data representation problems. It should be noted that in some circumstances, such as internationalization, the set of format strings is externally controlled by design. If the source of these format strings is trusted (e.g. only contained in library files that are only modifiable by the system administrator), then the external control might not itself pose a vulnerability.