gzip: arbitrary-file-write vulnerability

An arbitrary file write vulnerability was found in GNU gzip's zgrep utility. When zgrep is applied on the attacker's chosen file name (for example, a crafted file name), this can overwrite an attacker's content to an arbitrary attacker-selected file. This flaw occurs due to insufficient validation when processing filenames with two or more newlines where selected content and the target file names are embedded in crafted multi-line file names. This flaw allows a remote, low privileged attacker to force zgrep to write arbitrary files on the system.

Global Buffer Overflow in GNU gzip

GNU gzip contains a global buffer overflow vulnerability in the LZH decompression logic caused by improper reuse of shared global state between different decompression formats within a single execution. GNU gzip maintains a global array that is shared across the LZ77, LZW, and LZH decompression routines and is not reinitialized between files processed in the same invocation. By decompressing a specially crafted LZW file followed by a specially crafted LZH file in a single gzip -d command, an attacker can poison the shared global state and subsequently trigger an out‑of‑bounds read in the LZH decoder. The LZH decompression logic follows stale values left in the shared array, causing reads past the end of the allocated global buffer. This issue has been fixed in commits 63dbf6b3b9e6e781df1a6a64e609b10e23969681 and e7378c2d421be6a286922374425680bbe9ad8b7d.

Predictable Temporary File in GNU gzip

GNU gzip contains a vulnerability in the gzexe utility related to insecure temporary file handling. When the mktemp utility is not available in the user’s PATH, gzexe falls back to constructing a temporary file path based solely on the process ID (PID). This predictable filename is created without exclusive access or existence checks. A local attacker can pre‑create the predicted temporary file path as a symbolic link pointing to an arbitrary file writable by the victim. When gzexe runs, it follows the symlink and overwrites the target file, resulting in a time‑of‑check to time‑of‑use (TOCTOU) condition that allows arbitrary file overwrite. This issue has been fixed in the commit 4e6f8b24ab823146ab8776f0b7fe486ab34d4269

The (1) gzexe, (2) zdiff, and (3) znew scripts in the gzip package, as used by other packages such as ncompress, allows local users to overwrite files via a symlink attack on temporary files. NOTE: the znew vulnerability may overlap CVE-2003-0367.

gzip before 1.3 in Solaris 8, when called with the -f or -force flags, will change the permissions of files that are hard linked to the target files, which allows local users to view or modify these files.

security flaw

zgrep in gzip before 1.3.5 does not properly sanitize arguments, which allows local users to execute arbitrary commands via filenames that are injected into a sed script.

Buffer overflows in gzip 1.3x, 1.2.4, and other versions might allow attackers to execute code via a long file name, possibly remotely if gzip is run on an FTP server.

security flaw

Directory traversal vulnerability in gunzip -N in gzip 1.2.4 through 1.3.5 allows remote attackers to write to arbitrary directories via a .. (dot dot) in the original filename within a compressed file.

security flaw

Race condition in gzip 1.2.4, 1.3.3, and earlier, when decompressing a gzipped file, allows local users to modify permissions of arbitrary files via a hard link attack on a file while it is being decompressed, whose permissions are changed by gzip after the decompression is complete.

gzip: symlink attack on temporary files leads to arbitrary file overwrite

znew in the gzip package allows local users to overwrite arbitrary files via a symlink attack on temporary files.

gzexe in gzip 1.3.3 and earlier will execute an argument when the creation of a temp file fails instead of exiting the program, which could allow remote attackers or local users to execute arbitrary commands, a different vulnerability than CVE-1999-1332.

gzip: (64 bit) Integer underflow by decompressing LZW format files

Integer underflow in the unlzw function in unlzw.c in gzip before 1.4 on 64-bit platforms, as used in ncompress and probably others, allows remote attackers to cause a denial of service (application crash) or possibly execute arbitrary code via a crafted archive that uses LZW compression, leading to an array index error.

gzip: Missing input sanitation by decompressing dynamic Huffman code blocks

The huft_build function in inflate.c in gzip before 1.3.13 creates a hufts (aka huffman) table that is too small, which allows remote attackers to cause a denial of service (application crash or infinite loop) or possibly execute arbitrary code via a crafted archive. NOTE: this issue is caused by a CVE-2006-4334 regression.