Malicious PDF — malware analysis report

Static analysis result for SHA-256 4e99c5c6777ad421…

MALICIOUS

PDF

8.7 KB
MD5: 0dc0e9996b3448f1e3e980b2110ac526 SHA-1: 1e4bb6bfcdb9a88fac1e6bcf5960bb3772caf6f6 SHA-256: 4e99c5c6777ad421724129155687d35b689992dacb6cdc81bd0d3e9c22c35625
346 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.001 Malicious Link T1204.002 Malicious File

The PDF file contains multiple critical heuristic firings indicating exploitation of Adobe Reader vulnerabilities, specifically CVE-2009-0927, CVE-2007-5659, and CVE-2008-2992. These vulnerabilities are triggered by embedded JavaScript, which is heavily obfuscated and uses custom Base64 decoding to evade detection. The extracted JavaScript is designed to download and execute a second-stage payload, as indicated by the ClamAV detection 'Js.Exploit.Shellcode-18'. The presence of multiple exploit-related heuristics and the nature of the embedded script strongly suggest a malicious intent to compromise the user's system.

Heuristics 10

  • 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)
  • ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAV
    ClamAV flagged at least one file extracted from inside this sample. Even when the wrapping document carries no AV detection of its own, a hit on the carved artifact is a strong indicator the sample is a delivery vehicle.
  • OpenAction trigger high PDF_OPENACTION
    PDF has an /OpenAction — code runs automatically when opened
  • eval() call high PDF_EVAL
    eval() found — commonly used for obfuscated exploit execution (matched inside decoded stream)
  • 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. (matched inside decoded stream)
  • 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.

FilenameKindSourceSize
stream_000_off0000010d.js
11cb5b08a6c119fe2880251ad7c182aad5b61ab8ba66b529877cc59814755a57
decompressed-pdf-stream PDF FlateDecoded stream at offset 0x10D 19600 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 4 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
custom_b64_stage_000.js
6474402478c9cd53ca6dba6ff606c2fde1abf994f901b8e2323fc373b0b51f61
deobfuscated-js custom Base64 decoded JavaScript layer 2 (decompressed) at offset 0x487 10502 bytes
Detection
ClamAV: Js.Exploit.Shellcode-18
Obfuscation or payload: likely
Carved artifact contains 9 eval/decoder/string-building token(s).