Malicious PDF — malware analysis report

Static analysis result for SHA-256 a4bacb5422920b80…

MALICIOUS

PDF

40.0 KB
MD5: 3ac6e1af88f773de821a97bc1f9b70b7 SHA-1: f1af222431329189a5693225f106ce2968b9b980 SHA-256: a4bacb5422920b8041d9f031d59e974ebd63f0b672bf1b57b2c41dfdb4d43a48
198 Risk Score

Malware Insights

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

The PDF file contains embedded JavaScript and triggers a known vulnerability (CVE-2009-4324) related to media player annotations. The embedded JavaScript, specifically 'legacy_pdfkit_stage_000.js', is deobfuscated and appears to be designed to download and execute a second-stage payload. ClamAV detections further confirm the malicious nature of the file and its extracted artifacts.

Heuristics 6

  • 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)
  • ClamAV: Win.Trojan.Agent-36169 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Win.Trojan.Agent-36169
  • 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.
  • 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.
  • 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0008_000.js
a93a8a5f61d809ff10a9f6ea0be83cf2c8785e4494adf4afb1d65c224577449f
pdf-javascript-stream PDF /JS object 8 at offset 0x1E7 2019 bytes
Detection
ClamAV: Win.Trojan.Agent-36169
Obfuscation or payload: unlikely
legacy_pdfkit_stage_000.js
6615bafdfca3443f4e226384bdb5b622622cea29fad1cb3aad6a924ef5787e9e
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x9FE 2540 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).
legacy_pdfkit_stage_001.js
42025b552c7960b53abcd8cd732b01c8d109eccfdfefc352b9826c4d5807d414
deobfuscated-js cross-stage annotation API aliases at offset 0x1E7 81 bytes