Malicious PDF — malware analysis report

Static analysis result for SHA-256 4a346188154d07d2…

MALICIOUS

PDF

9.5 KB
MD5: e2919735d917f81df3104cd14733384f SHA-1: 3b432c3be78fcf818c3b199195ba5bd343a08f0a SHA-256: 4a346188154d07d242463769e0858df777b1eb287d900ba22a21e8da2f3e7631
186 Risk Score

Malware Insights

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

The sample is a PDF file that leverages the CVE-2007-5659 vulnerability, specifically using the Collab.collectEmailInfo function to execute embedded JavaScript. This JavaScript is heavily obfuscated but appears to be a stager designed to download and execute a second-stage payload. The presence of multiple deobfuscated JavaScript files indicates a complex execution chain.

Heuristics 7

  • 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)
  • ClamAV: Heuristics.PDF.ObfuscatedNameObject critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Heuristics.PDF.ObfuscatedNameObject
  • Annotation subject callee-key hex JavaScript stager high PDF_ANNOT_SUBJECT_CALLEE_HEX_STAGER
    PDF JavaScript uses syncAnnotScan()/getAnnots() to read an indirect annotation /Subject stream, percent-decodes it through marker replacement, then uses a callee.toString()-derived key to decode and eval the final exploit stage.
  • 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.
  • syncAnnotScan annotation-staging primitive low PDF_FOXIT_SYNCANNOTSCAN
    PDF JavaScript calls syncAnnotScan() — a no-op annotation-enumeration primitive used by exploit-kit JavaScript to stage payload reads from annotation /Subject fields before eval(). Not a vulnerable sink itself; rarely seen in legitimate PDFs. (matched in decompressed 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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0007_000.js
11b03694c4e705ab29873cc5e2c55342ee498b376ac2dc5f05ce17018ef44c38
pdf-javascript-stream PDF /JS object 7 at offset 0x19D 264 bytes
annotation_subject_callee_hex_stage_000.js
3ee0a05cc45dd85b446c6904232094921531e5bf305d35d0baf5e6ed300d9e85
deobfuscated-js annotation-subject callee-key decoded JavaScript at offset 0x14A 5088 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 5 eval/decoder/string-building token(s).
legacy_pdfkit_stage_001.js
8479c6e3fc297452e39c649c2b68c04965dacdea5a12ec95cb90d733222a7c58
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x2CC 12111 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s). Carved artifact contains 1 long base64-like blob(s).
deobfuscated.js
98bb02d0c0d383457c0d51f8643c47528c2116042227b3e33da4bc42daae482c
deobfuscated-js PDF JavaScript deobfuscation pass 76746 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).