Malicious PDF — malware analysis report

Static analysis result for SHA-256 00c926d8d4bc9b98…

MALICIOUS

PDF

9.3 KB
MD5: 6a00284ca11d53dbcc2de3a5ba233f09 SHA-1: c1faf1b33b88e051608523901a9efbf48f91b94e SHA-256: 00c926d8d4bc9b98f70329c04c3ca646257bf9a83f1ede90548bc8925ede89ae
278 Risk Score

Malware Insights

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

The PDF contains embedded JavaScript that leverages the CVE-2007-5659 vulnerability by using the `syncAnnotScan` and `getAnnots` primitives to extract and decode a payload. This payload is then evaluated, and the heuristics indicate it contains a URL for downloading a second-stage shellcode. The primary function of this PDF is to act as a downloader for further malicious activity.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 10

  • 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)
  • Adobe Reader APSB08-13 patch-range version gate (CVE-2007-5659) high CVE likely PDF_JS_ADOBE_APSB08_13_PATCH_GATE
    PDF JavaScript gates the exploit payload on (>= 8 && < 8.1.1) OR (< 7.1) — the Reader 7.0.x / 8.0–8.1.1 window patched by Adobe APSB08-13 for the CVE-2007-5659 Collab.collectEmailInfo buffer overflow. Only kits that target that exact bug check both of those patch points; benign scripts do not.
  • Generic recovered JavaScript exploit stage high PDF_GENERIC_STAGE_RECOVERY
    Bounded static stage recovery exposed hidden JavaScript through generic transforms such as null-byte collapse, percent decoding, marker replacement, arithmetic character codes, fromCharCode, numeric arrays, numeric-array minus-key decoders, alphabet-index arrays, /Producer half-difference metadata arrays, hex literals, marker-stripped Base64 literals, custom 6-bit XOR table decoders, or repeated-marker hex carriers. This rule is emitted only when the recovered stage contains exploit-like Acrobat JavaScript or shellcode markers.
  • 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.
  • PDF JavaScript shellcode contains an embedded download URL high PDF_JS_SHELLCODE_DOWNLOAD_URL
    Decoded PDF JavaScript shellcode contains a hardcoded http(s) URL stored as little-endian %uXXXX Unicode escapes. Reader exploit shellcode embeds the second-stage fetch URL this way and pulls it down with a urlmon/URLDownloadToFile-style download-and-execute (commodity downloader behaviour rather than a specific Acrobat CVE).
  • 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.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://xlgjewczfjqx.com/nte/avorp1tuta8.py/eU230d9c2eH3d8b0ec0V0100f060006R19036343102Tb483f079203l000cK7f443346

Extracted artifacts 5

Files carved from inside the sample during analysis.

FilenameKindSourceSize
javascript_obj0007_000.js
dc37160715dd481d0bf49e7af5079aad16ed0e66896c1ae05ca27000b3e4454e
pdf-javascript-stream PDF /JS object 7 at offset 0x19B 259 bytes
generic_stage_recovery_000.js
1f9c41bac023af5173acb947acb1765aece4fb2d478d8f77dfc696cb5d6327ed
deobfuscated-js generic stage recovery split-literal-normalize from JavaScript object 7 at offset 0x19B 249 bytes
annotation_subject_callee_hex_stage_000.js
429f075bc1e91b6d311038afc1105cc443a3f0a21e288be858ccbde7562680c1
deobfuscated-js annotation-subject callee-key decoded JavaScript at offset 0x14A 4966 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
496d21da5fcfcbe6b13ee1c7aa322fca7005e50803630331386271ead2286bbf
deobfuscated-js repeated-marker hex decoded JavaScript at offset 0x2D4 11868 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
6d949d38f239221829e4d74d7badca3c71ea90b92baa2c939cca551d6191d01e
deobfuscated-js PDF JavaScript deobfuscation pass 43073 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).