PDF malware analysis — malicious · c81a0a224195ab02

MALICIOUS

PDF

25.3 KB Created: 2011-72-51 03:25:00 Authoring application: String.fromCharCode

MD5: 1a4642f538233110b8788234c02070b0 SHA-1: 5259200250f546188389a394617c1a6f5dc6d543 SHA-256: c81a0a224195ab02fe3e853fb37a54c1b38061a2f6ec579b8ef2d2c9b4f6b5f9

376 Risk Score

Malware Insights

MITRE ATT&CK

T1059.001 JavaScript T1204.002 Malicious File

This PDF file contains embedded JavaScript that leverages multiple critical CVEs (CVE-2009-4324, CVE-2009-0927, CVE-2007-5659, CVE-2008-2992) through metadata manipulation and arithmetic stagers. The primary function appears to be the execution of obfuscated JavaScript, which is then deobfuscated into a larger payload. This deobfuscated script is designed to download and execute a second-stage payload, as indicated by the ML classifier's high confidence score and the presence of a stager script.

Machine Learning

Nyx PDF Classifier malicious score 1.0000

Heuristics 10

media.newPlayer — CVE-2009-4324 critical CVE exact CVE_2009_4324

PDF JavaScript calls media.newPlayer — CVE-2009-4324 is a use-after-free in Adobe Reader's multimedia plugin triggered by media.newPlayer(). Actively exploited as a zero-day in December 2009. (identified after JavaScript deobfuscation)
Collab.getIcon — CVE-2009-0927 critical CVE exact CVE_2009_0927

PDF JavaScript calls Collab.getIcon — CVE-2009-0927 is a stack buffer overflow in Adobe Reader triggered by Collab.getIcon() with a crafted argument. Allows arbitrary code execution. (identified after JavaScript deobfuscation)
Collab.collectEmailInfo — CVE-2007-5659 critical CVE exact CVE_2007_5659

PDF JavaScript calls Collab.collectEmailInfo — CVE-2007-5659 is a buffer overflow in Adobe Reader triggered by a long argument or heap-sprayed message field passed to Collab.collectEmailInfo(). Part of a series of Acrobat JS API exploits. (identified after JavaScript deobfuscation)
util.printf — CVE-2008-2992 critical CVE exact CVE_2008_2992

PDF JavaScript calls util.printf() — CVE-2008-2992 is a stack buffer overflow in Adobe Reader triggered by a long format-specifier argument. Widely exploited in the wild after disclosure. (identified after JavaScript deobfuscation)
PDF metadata arithmetic JavaScript stager high PDF_INFO_ARITHMETIC_JS_STAGER

PDF metadata hides JavaScript as arithmetic character-code tokens inside document information fields, then a launcher rebuilds it with String.fromCharCode and eval. The decoder is gated on metadata access from the launcher, a large arithmetic token table, and recovered exploit-like JavaScript.
PDF metadata JavaScript eval stager high PDF_METADATA_EVAL_STAGER

PDF JavaScript reads document metadata fields such as title, subject, or producer, decodes character data with parseInt/String.fromCharCode style helpers, and evals the recovered stage. This is a high-signal exploit-kit staging pattern.
JavaScript action low PDF_JAVASCRIPT

PDF contains a /JavaScript action. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
Embedded JS stream low PDF_JS

PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
String.fromCharCode low PDF_FROMCHARCODE

String.fromCharCode found — used to construct payload strings dynamically. Common in benign JavaScript libraries for codepoint manipulation, so this alone is informational; weaponised use is also caught by the dedicated fromCharCode-stage and exploit-shape rules.
Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE

One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.

Extracted artifacts 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`javascript_obj0001_000.js` `0fc17683f68b64310b2e9029c750f8e7df13a3c94e8fbbc90a979b7b104373b9`	pdf-javascript-stream	PDF /JS object 1 at offset 0x625B	515 bytes
`info_arithmetic_stage_000.js` `a93482f9b7adb1910e9f4f61779b9f875bcd7d7915b0f525f9b4fa1aec75c8e6`	deobfuscated-js	PDF /Info Title arithmetic JavaScript at offset 0x23	3660 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 11 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).

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