Multiple Vulnerabilities in Mirabilis ICQ Client

Advisory ID Internal

CORE-2003-0303

Advisory Information:

Date Published: 2003-05-05
Last Update: 2003-05-02
Advisory ID: CORE-2003-0303
Bugtraq IDs: 7461, 7462, 7463, 7464, 7465, 7466
CVE Names: CAN-2003-0235, CAN-2003-0236, CAN-2003-0237, CAN-2003-0238, CAN-2003-0239
CERT: VU#936164, VU#792988, VU#829860, VU#367156, VU#967316, VU#680788
Title: Multiple Vulnerabilities in Mirabilis ICQ Pro 2003a client

Class: Remote Code Execution; Denial of Service; Boundary Error Condition (Buffer Overflow); Design/implementation error.
Remotely Exploitable: Yes
Locally Exploitable: Yes

Vendors Contacted:

Mirabilis
We sent notifications mails to the following addresses: [email protected], [email protected], and [email protected], several times during March and April (2003-03-11, 2003-03-24, 2003-04-11) and never received an answer from Mirabilis.

Release Mode: USER RELEASE

Vulnerability Description:

Mirabilis ICQ client is a popular program that enables users to communicate through instant messaging, chat, sending emails, SMS and wireless-pager messages, as well as transfering files and URLs.

The ICQ client offers other client services, for more information about ICQ see: http://www.icq.com/products/whatisicq.html

Six security vulnerabilities were found that could lead to various forms of exploitation ranging from denying users the ability to use ICQ services to execution of arbitrary commands on vulnerable systems.
The following vulnerabilities were found:

[BID 7461, CAN-2003-0235, VU#936164] POP3 Client Format String in UIDL Field:
ICQ provides an integrated POP3 client vulnerable to a format string attack in the UIDL command server response string (the unique-id of a message). This vulnerability can be successfully exploited by an attacker able to impersonate the POP3 server.

[BID 7462, CAN-2003-0236, VU#792988] "Subject" signed overflow in POP3 Client:
ICQ provides an integrated POP3 client vulnerable to a 16bit sign overflow in the "Subject" field of e-mail headers. An attacker may be able to execute arbitrary commands by sending a malformed e-mail header to a vulnerable client.

[BID 7463, CAN-2003-0236, VU#829860] "Date" signed overflow in POP3 Client:
ICQ provides an integrated POP3 client vulnerable to a 16bit sign overflow in the "Date" field of e-mail headers. An attacker may be able to execute arbitrary commands by sending a malformed e-mail header to a vulnerable client.

[BID 7464, CAN-2003-0237, VU#367156] ICQ Features on Demand spoofing attack:
ICQ provides a semi-automated functionality for upgrading client services (i.e.: ICQ Phone, ICQ Web Search, etc) called "ICQ Features on Demand" vulnerable to a spoofing attack due to hard-coded information and lack of authentication signatures.
By taking advantage of this vulnerability, an attacker will be able to install malicious software that could lead to execution of arbitrary commands as well as other important security breaches.

[BID 7465, CAN-2003-0238, VU#967316] Message advertisements denial of service attack:
ICQ displays advertisements inside a message window (called 'Message Session') by using a proprietary HTML parsing/rendering library vulnerable to malformed tags input.
By impersonating the static ADS server, an attacker may send malformed HTML code to the ADS rendering window freezing the ICQ interface and using 100% CPU.

[BID 7466, CAN-2003-0239, VU#680788] Input validation error in ICQ's GIF parsing/rendering library:
ICQ implements its own image parsing/rendering library (found in 'icqateimg32.dll') vulnerable to an input validation error, causing a denial of service. The problem is triggered while parsing GIF89a headers.

Vulnerable Packages:

Mirabilis ICQ Pro 2003a and previous versions.

Credits:

These vulnerabilities were found by Lucas Lavarello, Daniel Benmergui, Norberto Kueffner and Fernando Russ from Core Security Technologies during Bugweek 2003 (March 3-7, 2003).

Technical Description:

[BID 7461, CAN-2003-0235, VU#936164]
POP3 Client Format String in UIDL Field

ICQ's integrated POP3 client is a COM object found inside POP3.dll.
The client is vulnerable to a format string attack in the UIDL command server response string (the unique-id of a message) :

"The unique-id of a message is an arbitrary server-determined string, consisting of one to 70 characters in the range 0x21 to 0x7E, which uniquely identifies a message within a maildrop and which persists across sessions" as described in RFC 1939 (found in http://www.ietf.org/rfc/rfc1939.txt).

By the insertion of format strings as part of a UIDL response message, the POP3 client can be forced to execute arbitrary commands.

[BID 7462, CAN-2003-0236, VU#792988]
"Subject" signed overflow in POP3 Client

ICQ's integrated POP3 client is a COM object found inside POP3.dll.
The client is vulnerable to a sign overflow attack in the "Subject" field of e-mail headers.

The length of the "Subject" field is stored in a 16 bit (short) signed integer, allowing an attacker to send a malicious e-mail along with a long "Subject" field of around 33k octets overflowing the sign of the variable and causing a negative value.

This attack results in the client throwing a self unhandled exception, crashing the client.

[BID 7463, CAN-2003-0236, VU#829860]
"Date" signed overflow in POP3 Client

ICQ's integrated POP3 client is a COM object found inside POP3.dll.
The client is vulnerable to a sign overflow attack in the "Date" field of e-mail headers.

The length of the "Date" field is stored in a 16 bit (short) signed integer, allowing an attacker to send a malicious e-mail along with a long "Date" field of around 32k octets overflowing the sign of the variable and causing a negative value.

This attack results in the client throwing a handled exception, instantly closing the client.

[BID 7464, CAN-2003-0237, VU#367156]
ICQ Features on Demand spoofing attack

The URL from where the requested 'Features on Demand' are downloaded is hard-coded inside a file called "Packages.ini" found inside the subdirectory "\DataFiles" in ICQ's default installation path. The value named "DataURL" which belongs to the section "[General]" holds a static address from where the client will download user requested packages.

An attack is possible due to the lack of authentication methods applied to new downloaded packages. An attacker will be able to impersonate the 'package repository service' by spoofing the hard-coded address, being able to install malicious software that could lead to the execution of arbitrary commands as well as other important security breaches.

[BID 7465, CAN-2003-0238, VU#967316]
Message advertisements denial of service attack

The URL from where the HTML ads are downloaded has the following format: "http://web.icq.com/client/ate/ad-handler/ad_468/0,,[RANDOM],00.htm"
Being [RANDOM] a signed 16 bit random number. Note that the "," characters don't get encoded in their respective US-ASCII escape encoding.

The HTTP request follows certain rules:
- It is an HTTP/1.0 request
- The request has a "Refer:" to itself
- The "User-Agent:" is "Mozilla/4.08 [en] (WinNT; U; Nav)"
- The "Accept:" header must be "*/*"

The HTML parsing/rendering library is vulnerable to erroneous attributes specified in the <table> tag. By specifying a "width" attribute of value "-1", the library will use 100% CPU, freezing the ICQ interface.

The attack is possible due to the lack of authentication methods applied to requests. An attacker will be able to impersonate the "ADS server" by spoofing the semi hard-coded address, being able to deny to users the usage of ICQ services.

[BID 7466, CAN-2003-0239, VU#680788]
Input validation error in ICQ's GIF parsing/rendering library

While parsing GIF89a header files, ICQ's GIF parsing/rendering library expects either an existing GCT (Global Color Table) or an LCT (Local Color Table) after an "Image Descriptor". When none of these color tables exist, the library will malfunction leading to a denial of service.

The GIF89a file format has a section called "Logical Screen Descriptor":
(from GIF89a specification, which can be found at ftp://ftp.ncsa.uiuc.edu/misc/file.formats/graphics.formats/gif89a.doc)

<Packed Fields> = Global Color Table Flag 1 Bit
Color Resolution 3 Bits
Sort Flag 1 Bit
Size of Global Color Table 3 Bits

This section describes the screen size, the pixel aspect ratio, background color index, etc, and a set of fields (<Packed Fields>) which has the "Global Color Table Flag" bit indicating the presence of a Global Color Table; if the flag is set, the Global Color Table will immediately follow the "Logical Screen Descriptor", this flag also selects the interpretation of the "Background Color Index"; if the flag is set, the value of the "Background Color Index" field should be used as the table index of the background color.

After the "Logical Screen Descriptor" or (if present) the "Global Color Table", there is an "Image Descriptor" per image compressed inside the GIF file with the following format:

<Packed Fields> = Local Color Table Flag 1 Bit
Interlace Flag 1 Bit
Sort Flag 1 Bit
Reserved 2 Bits
Size of Local Color Table 3 Bits

(From GIF89a specification)

The set of fields (<Packed Fields>) found in an "Image Descriptor" include a "Local Color Table Flag" bit indicating the presence of a Local Color Table; if the flag is set, the Local Color Table will immediately follow the "Image Descriptor".

About Core Security:

Core Security develops strategic security solutions for Fortune 1000 corporations, government agencies and military organizations. The company offers information security software and services designed to assess risk and protect and manage information assets.

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